From b763b6a31b262dcb11adef5ef35535da148309d5 Mon Sep 17 00:00:00 2001
From: Vishwajith Shettigar
 <76042077+Vishwajith-Shettigar@users.noreply.github.com>
Date: Wed, 13 Mar 2024 05:28:22 +0530
Subject: [PATCH] Fix part of #5070: Display empty answer message in Math
 expressions input interaction. (#5317)

<!-- READ ME FIRST: Please fill in the explanation section below and
check off every point from the Essential Checklist! -->
## Explanation
Fix part of #5070, In Math expressions Interaction UI, leave submit
button enabled when answer is empty. Show an error on submitting an
empty answer.

MathExpressionInteractionsViewTestActivity added to
accessibility_label_exemptions and test_file_exemptions files.


### Numeric expression


[numerix_expression.webm](https://github.com/oppia/oppia-android/assets/76042077/ce7e3e2a-e209-4197-ac3b-4a4ab281ac53)


### Algebraic expression


[algebraic_expression.webm](https://github.com/oppia/oppia-android/assets/76042077/62222fe4-9cef-49cf-a86d-d74a0908d0a0)


### Math equation


[math_equation.webm](https://github.com/oppia/oppia-android/assets/76042077/fb097e88-c8b2-4159-bdcf-2b4e64386d78)



<!--
- Explain what your PR does. If this PR fixes an existing bug, please
include
- "Fixes #bugnum:" in the explanation so that GitHub can auto-close the
issue
  - when this PR is merged.
  -->

## Essential Checklist
<!-- Please tick the relevant boxes by putting an "x" in them. -->
- [x] The PR title and explanation each start with "Fix #bugnum: " (If
this PR fixes part of an issue, prefix the title with "Fix part of
#bugnum: ...".)
- [x] Any changes to
[scripts/assets](https://github.com/oppia/oppia-android/tree/develop/scripts/assets)
files have their rationale included in the PR explanation.
- [x] The PR follows the [style
guide](https://github.com/oppia/oppia-android/wiki/Coding-style-guide).
- [x] The PR does not contain any unnecessary code changes from Android
Studio
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#undo-unnecessary-changes)).
- [x] The PR is made from a branch that's **not** called "develop" and
is up-to-date with "develop".
- [x] The PR is **assigned** to the appropriate reviewers
([reference](https://github.com/oppia/oppia-android/wiki/Guidance-on-submitting-a-PR#clarification-regarding-assignees-and-reviewers-section)).

## For UI-specific PRs only
<!-- Delete these section if this PR does not include UI-related
changes. -->
If your PR includes UI-related changes, then:
- Add screenshots for portrait/landscape for both a tablet & phone of
the before & after UI changes
- For the screenshots above, include both English and pseudo-localized
(RTL) screenshots (see [RTL
guide](https://github.com/oppia/oppia-android/wiki/RTL-Guidelines))
- Add a video showing the full UX flow with a screen reader enabled (see
[accessibility
guide](https://github.com/oppia/oppia-android/wiki/Accessibility-A11y-Guide))
- For PRs introducing new UI elements or color changes, both light and
dark mode screenshots must be included
- Add a screenshot demonstrating that you ran affected Espresso tests
locally & that they're passing
---
 app/src/main/AndroidManifest.xml              |   1 +
 .../app/activity/ActivityComponentImpl.kt     |   2 +
 .../MathExpressionInteractionsViewModel.kt    |  50 ++++--
 .../InputInteractionViewTestActivity.kt       |  39 -----
 ...hExpressionInteractionsViewTestActivity.kt | 147 ++++++++++++++++++
 .../activity_input_interaction_view_test.xml  |  15 --
 ..._math_expression_interaction_view_test.xml |  64 ++++++++
 app/src/main/res/values/strings.xml           |   3 +
 .../MathExpressionInteractionsViewTest.kt     | 106 +++++++++++--
 .../app/player/state/StateFragmentTest.kt     |  46 +++---
 model/src/main/proto/arguments.proto          |  12 ++
 .../accessibility_label_exemptions.textproto  |   1 +
 scripts/assets/test_file_exemptions.textproto |   1 +
 13 files changed, 389 insertions(+), 98 deletions(-)
 create mode 100644 app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity.kt
 create mode 100644 app/src/main/res/layout/activity_math_expression_interaction_view_test.xml

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index dd85589b1b9..41d1ce55918 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -224,6 +224,7 @@
     <activity android:name=".app.testing.InputInteractionViewTestActivity" />
     <activity android:name=".app.testing.RatioInputInteractionViewTestActivity" />
     <activity android:name=".app.testing.ImageRegionSelectionTestActivity" />
+    <activity android:name=".app.testing.MathExpressionInteractionsViewTestActivity" />
     <activity android:name=".app.testing.ImageViewBindingAdaptersTestActivity" />
     <activity android:name=".app.testing.ListItemLeadingMarginSpanTestActivity" />
     <activity android:name=".app.testing.MarginBindingAdaptersTestActivity" />
diff --git a/app/src/main/java/org/oppia/android/app/activity/ActivityComponentImpl.kt b/app/src/main/java/org/oppia/android/app/activity/ActivityComponentImpl.kt
index a4f6d5a6d5d..12c9b38749e 100644
--- a/app/src/main/java/org/oppia/android/app/activity/ActivityComponentImpl.kt
+++ b/app/src/main/java/org/oppia/android/app/activity/ActivityComponentImpl.kt
@@ -73,6 +73,7 @@ import org.oppia.android.app.testing.ImageViewBindingAdaptersTestActivity
 import org.oppia.android.app.testing.InputInteractionViewTestActivity
 import org.oppia.android.app.testing.ListItemLeadingMarginSpanTestActivity
 import org.oppia.android.app.testing.MarginBindingAdaptersTestActivity
+import org.oppia.android.app.testing.MathExpressionInteractionsViewTestActivity
 import org.oppia.android.app.testing.NavigationDrawerTestActivity
 import org.oppia.android.app.testing.PoliciesFragmentTestActivity
 import org.oppia.android.app.testing.ProfileChooserFragmentTestActivity
@@ -152,6 +153,7 @@ interface ActivityComponentImpl :
   fun inject(imageViewBindingAdaptersTestActivity: ImageViewBindingAdaptersTestActivity)
   fun inject(inputInteractionViewTestActivity: InputInteractionViewTestActivity)
   fun inject(textInputInteractionViewTestActivity: TextInputInteractionViewTestActivity)
+  fun inject(mathExpressionInteractionsViewTestActivity: MathExpressionInteractionsViewTestActivity)
   fun inject(ratioInputInteractionViewTestActivity: RatioInputInteractionViewTestActivity)
   fun inject(licenseListActivity: LicenseListActivity)
   fun inject(licenseTextViewerActivity: LicenseTextViewerActivity)
diff --git a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/MathExpressionInteractionsViewModel.kt b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/MathExpressionInteractionsViewModel.kt
index 132c988774b..06b6bb3a47c 100644
--- a/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/MathExpressionInteractionsViewModel.kt
+++ b/app/src/main/java/org/oppia/android/app/player/state/itemviewmodel/MathExpressionInteractionsViewModel.kt
@@ -105,12 +105,18 @@ class MathExpressionInteractionsViewModel private constructor(
         override fun onPropertyChanged(sender: Observable, propertyId: Int) {
           errorOrAvailabilityCheckReceiver.onPendingAnswerErrorOrAvailabilityCheck(
             pendingAnswerError,
-            answerText.isNotEmpty()
+            inputAnswerAvailable = true // Allow blank answer submission.
           )
         }
       }
     errorMessage.addOnPropertyChangedCallback(callback)
     isAnswerAvailable.addOnPropertyChangedCallback(callback)
+
+    // Initializing with default values so that submit button is enabled by default.
+    errorOrAvailabilityCheckReceiver.onPendingAnswerErrorOrAvailabilityCheck(
+      pendingAnswerError = null,
+      inputAnswerAvailable = true
+    )
   }
 
   override fun getPendingAnswer(): UserAnswer = UserAnswer.newBuilder().apply {
@@ -147,18 +153,16 @@ class MathExpressionInteractionsViewModel private constructor(
   }.build()
 
   override fun checkPendingAnswerError(category: AnswerErrorCategory): String? {
-    if (answerText.isNotEmpty()) {
-      pendingAnswerError = when (category) {
-        // There's no support for real-time errors.
-        AnswerErrorCategory.REAL_TIME -> null
-        AnswerErrorCategory.SUBMIT_TIME -> {
-          interactionType.computeSubmitTimeError(
-            answerText.toString(), allowedVariables, resourceHandler
-          )
-        }
+    pendingAnswerError = when (category) {
+      // There's no support for real-time errors.
+      AnswerErrorCategory.REAL_TIME -> null
+      AnswerErrorCategory.SUBMIT_TIME -> {
+        interactionType.computeSubmitTimeError(
+          answerText.toString(), allowedVariables, resourceHandler
+        )
       }
-      errorMessage.set(pendingAnswerError)
     }
+    errorMessage.set(pendingAnswerError)
     return pendingAnswerError
   }
 
@@ -290,7 +294,10 @@ class MathExpressionInteractionsViewModel private constructor(
   }
 
   private companion object {
-    private enum class InteractionType(
+    /**
+     * Enum class representing different types of interactions in a mathematical expression input field.
+     */
+    enum class InteractionType(
       val viewType: ViewType,
       @StringRes val defaultHintTextStringId: Int,
       val hasPlaceholder: Boolean,
@@ -420,6 +427,25 @@ class MathExpressionInteractionsViewModel private constructor(
         allowedVariables: List<String>,
         appLanguageResourceHandler: AppLanguageResourceHandler
       ): String? {
+        if (answerText.isBlank()) {
+          return when (this) {
+            NUMERIC_EXPRESSION -> {
+              appLanguageResourceHandler.getStringInLocale(
+                R.string.numeric_expression_error_empty_input
+              )
+            }
+            ALGEBRAIC_EXPRESSION -> {
+              appLanguageResourceHandler.getStringInLocale(
+                R.string.algebraic_expression_error_empty_input
+              )
+            }
+            MATH_EQUATION -> {
+              appLanguageResourceHandler.getStringInLocale(
+                R.string.math_equation_error_empty_input
+              )
+            }
+          }
+        }
         return when (val parseResult = parseAnswer(answerText, allowedVariables)) {
           is MathParsingResult.Failure -> when (val error = parseResult.error) {
             is DisabledVariablesInUseError -> {
diff --git a/app/src/main/java/org/oppia/android/app/testing/InputInteractionViewTestActivity.kt b/app/src/main/java/org/oppia/android/app/testing/InputInteractionViewTestActivity.kt
index 86e41201dad..20706aa12a3 100644
--- a/app/src/main/java/org/oppia/android/app/testing/InputInteractionViewTestActivity.kt
+++ b/app/src/main/java/org/oppia/android/app/testing/InputInteractionViewTestActivity.kt
@@ -10,18 +10,12 @@ import org.oppia.android.app.activity.ActivityComponentImpl
 import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
 import org.oppia.android.app.customview.interaction.NumericInputInteractionView
 import org.oppia.android.app.model.InputInteractionViewTestActivityParams
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType.ALGEBRAIC_EXPRESSION
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType.MATH_EQUATION
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType.MATH_INTERACTION_TYPE_UNSPECIFIED
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType.NUMERIC_EXPRESSION
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType.UNRECOGNIZED
 import org.oppia.android.app.model.Interaction
 import org.oppia.android.app.model.UserAnswer
 import org.oppia.android.app.model.WrittenTranslationContext
 import org.oppia.android.app.player.state.answerhandling.AnswerErrorCategory
 import org.oppia.android.app.player.state.answerhandling.InteractionAnswerErrorOrAvailabilityCheckReceiver
 import org.oppia.android.app.player.state.answerhandling.InteractionAnswerReceiver
-import org.oppia.android.app.player.state.itemviewmodel.MathExpressionInteractionsViewModel
 import org.oppia.android.app.player.state.itemviewmodel.NumericInputViewModel
 import org.oppia.android.app.player.state.itemviewmodel.StateItemViewModel
 import org.oppia.android.app.player.state.itemviewmodel.StateItemViewModel.InteractionItemFactory
@@ -30,7 +24,6 @@ import org.oppia.android.databinding.ActivityInputInteractionViewTestBinding
 import org.oppia.android.util.extensions.getProtoExtra
 import org.oppia.android.util.extensions.putProtoExtra
 import javax.inject.Inject
-import org.oppia.android.app.player.state.itemviewmodel.MathExpressionInteractionsViewModel.FactoryImpl.FactoryFactoryImpl as MathExpViewModelFactoryFactoryImpl
 
 /**
  * This is a dummy activity to test input interaction views.
@@ -46,12 +39,8 @@ class InputInteractionViewTestActivity :
   @Inject
   lateinit var numericInputViewModelFactory: NumericInputViewModel.FactoryImpl
 
-  @Inject
-  lateinit var mathExpViewModelFactoryFactory: MathExpViewModelFactoryFactoryImpl
-
   val numericInputViewModel by lazy { numericInputViewModelFactory.create<NumericInputViewModel>() }
 
-  lateinit var mathExpressionViewModel: MathExpressionInteractionsViewModel
   lateinit var writtenTranslationContext: WrittenTranslationContext
 
   override fun onCreate(savedInstanceState: Bundle?) {
@@ -67,36 +56,8 @@ class InputInteractionViewTestActivity :
         InputInteractionViewTestActivityParams.getDefaultInstance()
       )
     writtenTranslationContext = params.writtenTranslationContext
-    when (params.mathInteractionType) {
-      NUMERIC_EXPRESSION -> {
-        mathExpressionViewModel =
-          mathExpViewModelFactoryFactory
-            .createFactoryForNumericExpression()
-            .create(interaction = params.interaction)
-      }
-      ALGEBRAIC_EXPRESSION -> {
-        mathExpressionViewModel =
-          mathExpViewModelFactoryFactory
-            .createFactoryForAlgebraicExpression()
-            .create(interaction = params.interaction)
-      }
-      MATH_EQUATION -> {
-        mathExpressionViewModel =
-          mathExpViewModelFactoryFactory
-            .createFactoryForMathEquation()
-            .create(interaction = params.interaction)
-      }
-      MATH_INTERACTION_TYPE_UNSPECIFIED, UNRECOGNIZED, null -> {
-        // Default to numeric expression arbitrarily (since something needs to be defined).
-        mathExpressionViewModel =
-          mathExpViewModelFactoryFactory
-            .createFactoryForNumericExpression()
-            .create(interaction = params.interaction)
-      }
-    }
 
     binding.numericInputViewModel = numericInputViewModel
-    binding.mathExpressionInteractionsViewModel = mathExpressionViewModel
   }
 
   fun getPendingAnswerErrorOnSubmitClick(v: View) {
diff --git a/app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity.kt b/app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity.kt
new file mode 100644
index 00000000000..55219840ea9
--- /dev/null
+++ b/app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity.kt
@@ -0,0 +1,147 @@
+package org.oppia.android.app.testing
+
+import android.content.Context
+import android.content.Intent
+import android.os.Bundle
+import android.view.View
+import androidx.databinding.DataBindingUtil
+import org.oppia.android.R
+import org.oppia.android.app.activity.ActivityComponentImpl
+import org.oppia.android.app.activity.InjectableAutoLocalizedAppCompatActivity
+import org.oppia.android.app.model.Interaction
+import org.oppia.android.app.model.MathExpressionInteractionsViewTestActivityParams
+import org.oppia.android.app.model.MathExpressionInteractionsViewTestActivityParams.MathInteractionType
+import org.oppia.android.app.model.UserAnswer
+import org.oppia.android.app.model.WrittenTranslationContext
+import org.oppia.android.app.player.state.answerhandling.AnswerErrorCategory
+import org.oppia.android.app.player.state.answerhandling.InteractionAnswerErrorOrAvailabilityCheckReceiver
+import org.oppia.android.app.player.state.answerhandling.InteractionAnswerReceiver
+import org.oppia.android.app.player.state.itemviewmodel.MathExpressionInteractionsViewModel
+import org.oppia.android.app.player.state.itemviewmodel.StateItemViewModel
+import org.oppia.android.app.player.state.listener.StateKeyboardButtonListener
+import org.oppia.android.databinding.ActivityMathExpressionInteractionViewTestBinding
+import org.oppia.android.util.extensions.getProtoExtra
+import org.oppia.android.util.extensions.putProtoExtra
+import javax.inject.Inject
+
+/**
+ * This is a dummy activity to test input interaction views.
+ * It contains [MathExpressionInteractionsView].
+ */
+class MathExpressionInteractionsViewTestActivity :
+  InjectableAutoLocalizedAppCompatActivity(),
+  StateKeyboardButtonListener,
+  InteractionAnswerErrorOrAvailabilityCheckReceiver,
+  InteractionAnswerReceiver {
+
+  private lateinit var binding:
+    ActivityMathExpressionInteractionViewTestBinding
+
+  /**
+   * Injects the [MathExpressionInteractionsViewModel.FactoryImpl] for creating
+   * [MathExpressionInteractionsViewModel] instances.
+   */
+  @Inject
+  lateinit var mathExpViewModelFactoryFactory:
+    MathExpressionInteractionsViewModel.FactoryImpl.FactoryFactoryImpl
+
+  /** The [MathExpressionInteractionsViewModel] instance. */
+  lateinit var mathExpressionViewModel: MathExpressionInteractionsViewModel
+
+  /** Gives access to the translation context. */
+  lateinit var writtenTranslationContext: WrittenTranslationContext
+
+  override fun onCreate(savedInstanceState: Bundle?) {
+    super.onCreate(savedInstanceState)
+    (activityComponent as ActivityComponentImpl).inject(this)
+    binding = DataBindingUtil.setContentView<ActivityMathExpressionInteractionViewTestBinding>(
+      this, R.layout.activity_math_expression_interaction_view_test
+    )
+    val params =
+      intent.getProtoExtra(
+        TEST_ACTIVITY_PARAMS_ARGUMENT_KEY,
+        MathExpressionInteractionsViewTestActivityParams.getDefaultInstance()
+      )
+    writtenTranslationContext = params.writtenTranslationContext
+    when (params.mathInteractionType) {
+      MathInteractionType.NUMERIC_EXPRESSION -> {
+        mathExpressionViewModel =
+          mathExpViewModelFactoryFactory
+            .createFactoryForNumericExpression()
+            .create(interaction = params.interaction)
+      }
+      MathInteractionType.ALGEBRAIC_EXPRESSION -> {
+        mathExpressionViewModel =
+          mathExpViewModelFactoryFactory
+            .createFactoryForAlgebraicExpression()
+            .create(interaction = params.interaction)
+      }
+      MathInteractionType.MATH_EQUATION -> {
+        mathExpressionViewModel =
+          mathExpViewModelFactoryFactory
+            .createFactoryForMathEquation()
+            .create(interaction = params.interaction)
+      }
+      MathInteractionType.MATH_INTERACTION_TYPE_UNSPECIFIED,
+      MathInteractionType.UNRECOGNIZED, null -> {
+        // Default to numeric expression arbitrarily (since something needs to be defined).
+        mathExpressionViewModel =
+          mathExpViewModelFactoryFactory
+            .createFactoryForNumericExpression()
+            .create(interaction = params.interaction)
+      }
+    }
+
+    binding.mathExpressionInteractionsViewModel = mathExpressionViewModel
+  }
+
+  /** Checks submit-time errors. */
+  fun getPendingAnswerErrorOnSubmitClick(v: View) {
+    mathExpressionViewModel.checkPendingAnswerError(AnswerErrorCategory.SUBMIT_TIME)
+  }
+
+  override fun onPendingAnswerErrorOrAvailabilityCheck(
+    pendingAnswerError: String?,
+    inputAnswerAvailable: Boolean
+  ) {
+    binding.submitButton.isEnabled = pendingAnswerError == null
+  }
+
+  override fun onAnswerReadyForSubmission(answer: UserAnswer) {
+  }
+
+  override fun onEditorAction(actionCode: Int) {
+  }
+
+  private inline fun <reified T : StateItemViewModel> StateItemViewModel
+  .InteractionItemFactory.create(
+    interaction: Interaction = Interaction.getDefaultInstance()
+  ): T {
+    return create(
+      entityId = "fake_entity_id",
+      hasConversationView = false,
+      interaction = interaction,
+      interactionAnswerReceiver = this@MathExpressionInteractionsViewTestActivity,
+      answerErrorReceiver = this@MathExpressionInteractionsViewTestActivity,
+      hasPreviousButton = false,
+      isSplitView = false,
+      writtenTranslationContext,
+      timeToStartNoticeAnimationMs = null
+    ) as T
+  }
+
+  companion object {
+    private const val TEST_ACTIVITY_PARAMS_ARGUMENT_KEY =
+      "MathExpressionInteractionsViewTestActivity.params"
+
+    /** Function to create intent for MathExpressionInteractionsViewTestActivity. */
+    fun createIntent(
+      context: Context,
+      extras: MathExpressionInteractionsViewTestActivityParams
+    ): Intent {
+      return Intent(context, MathExpressionInteractionsViewTestActivity::class.java).also {
+        it.putProtoExtra(TEST_ACTIVITY_PARAMS_ARGUMENT_KEY, extras)
+      }
+    }
+  }
+}
diff --git a/app/src/main/res/layout/activity_input_interaction_view_test.xml b/app/src/main/res/layout/activity_input_interaction_view_test.xml
index 9a7a8b277f3..c60eb2fec5e 100644
--- a/app/src/main/res/layout/activity_input_interaction_view_test.xml
+++ b/app/src/main/res/layout/activity_input_interaction_view_test.xml
@@ -11,9 +11,6 @@
       name="numericInputViewModel"
       type="org.oppia.android.app.player.state.itemviewmodel.NumericInputViewModel" />
 
-    <variable
-      name="mathExpressionInteractionsViewModel"
-      type="org.oppia.android.app.player.state.itemviewmodel.MathExpressionInteractionsViewModel" />
   </data>
 
   <ScrollView
@@ -61,18 +58,6 @@
         android:textSize="12sp"
         android:visibility="@{numericInputViewModel.errorMessage.length() > 0 ? View.VISIBLE : View.INVISIBLE}" />
 
-      <org.oppia.android.app.customview.interaction.MathExpressionInteractionsView
-        android:id="@+id/test_math_expression_input_interaction_view"
-        style="@style/InputInteractionEditText"
-        android:inputType="text"
-        android:minHeight="48dp"
-        android:text="@={mathExpressionInteractionsViewModel.answerText}"
-        app:layout_constraintEnd_toEndOf="parent"
-        app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toTopOf="parent"
-        app:placeholder="@{mathExpressionInteractionsViewModel.hintText}"
-        app:textChangedListener="@{mathExpressionInteractionsViewModel.answerTextWatcher}" />
-
       <Button
         android:id="@+id/submit_button"
         style="@style/StateButtonActive"
diff --git a/app/src/main/res/layout/activity_math_expression_interaction_view_test.xml b/app/src/main/res/layout/activity_math_expression_interaction_view_test.xml
new file mode 100644
index 00000000000..2df1211932b
--- /dev/null
+++ b/app/src/main/res/layout/activity_math_expression_interaction_view_test.xml
@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  xmlns:tools="http://schemas.android.com/tools">
+
+  <data>
+
+    <import type="android.view.View" />
+
+    <variable
+      name="mathExpressionInteractionsViewModel"
+      type="org.oppia.android.app.player.state.itemviewmodel.MathExpressionInteractionsViewModel" />
+  </data>
+  <ScrollView
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+    <LinearLayout
+      android:layout_width="match_parent"
+      android:layout_height="wrap_content"
+      android:descendantFocusability="beforeDescendants"
+      android:focusableInTouchMode="true"
+      android:gravity="center"
+      android:orientation="vertical"
+      tools:context=".app.testing.MathExpressionInteractionsViewTestActivity">
+
+      <org.oppia.android.app.customview.interaction.MathExpressionInteractionsView
+        android:id="@+id/test_math_expression_input_interaction_view"
+        style="@style/InputInteractionEditText"
+        android:minHeight="48dp"
+        app:placeholder="@{mathExpressionInteractionsViewModel.hintText}"
+        android:inputType="text"
+        android:text="@={mathExpressionInteractionsViewModel.answerText}"
+        app:textChangedListener="@{mathExpressionInteractionsViewModel.answerTextWatcher}"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent"/>
+
+      <TextView
+        android:id="@+id/math_expression_input_error"
+        style="@style/TextViewStart"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_marginStart="16dp"
+        android:layout_marginEnd="8dp"
+        android:fontFamily="sans-serif"
+        android:minHeight="32dp"
+        android:text="@{mathExpressionInteractionsViewModel.errorMessage}"
+        android:textColor="@color/component_color_shared_input_error_color"
+        android:textSize="12sp"
+        android:visibility="@{mathExpressionInteractionsViewModel.errorMessage.length() > 0 ? View.VISIBLE : View.INVISIBLE}" />
+
+      <Button
+        android:id="@+id/submit_button"
+        style="@style/StateButtonActive"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_margin="8dp"
+        android:text="@string/submit_button_text"
+        android:onClick="getPendingAnswerErrorOnSubmitClick"
+        android:textColor="@color/component_color_shared_secondary_4_text_color" />
+
+    </LinearLayout>
+  </ScrollView>
+</layout>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index cdd0763d8fd..54dc913b9da 100755
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -104,8 +104,11 @@
   <string name="numeric_input_hint">Enter a number.</string>
   <string name="number_with_units_input_hint_text">Write numbers with units here.</string>
   <string name="numeric_expression_default_hint_text">Type an expression here, using only numbers.</string>
+  <string name="numeric_expression_error_empty_input">Enter a numeric expression to continue.</string>
   <string name="algebraic_expression_default_hint_text">Type an expression here.</string>
+  <string name="algebraic_expression_error_empty_input">Enter an algebraic expression to continue.</string>
   <string name="math_equation_default_hint_text">Type an equation here.</string>
+  <string name="math_equation_error_empty_input">Enter an equation to continue.</string>
   <string name="math_expression_error_spaces_in_numerical_input">Please remove the spaces between numbers in your answer.</string>
   <string name="math_expression_error_unbalanced_parentheses">Please close or remove parentheses.</string>
   <string name="math_expression_error_single_redundant_parentheses">Please remove the parentheses around the whole answer: \'%s\'.</string>
diff --git a/app/src/sharedTest/java/org/oppia/android/app/customview/interaction/MathExpressionInteractionsViewTest.kt b/app/src/sharedTest/java/org/oppia/android/app/customview/interaction/MathExpressionInteractionsViewTest.kt
index 2b8ea2dc02d..606db46927f 100644
--- a/app/src/sharedTest/java/org/oppia/android/app/customview/interaction/MathExpressionInteractionsViewTest.kt
+++ b/app/src/sharedTest/java/org/oppia/android/app/customview/interaction/MathExpressionInteractionsViewTest.kt
@@ -7,9 +7,11 @@ import androidx.appcompat.app.AppCompatActivity
 import androidx.test.core.app.ActivityScenario
 import androidx.test.core.app.ApplicationProvider
 import androidx.test.espresso.Espresso.onView
+import androidx.test.espresso.action.ViewActions.click
 import androidx.test.espresso.assertion.ViewAssertions.matches
 import androidx.test.espresso.matcher.ViewMatchers.withHint
 import androidx.test.espresso.matcher.ViewMatchers.withId
+import androidx.test.espresso.matcher.ViewMatchers.withText
 import com.google.common.truth.Truth.assertThat
 import com.google.common.truth.extensions.proto.LiteProtoTruth.assertThat
 import dagger.Component
@@ -31,9 +33,9 @@ import org.oppia.android.app.application.testing.TestingBuildFlavorModule
 import org.oppia.android.app.devoptions.DeveloperOptionsModule
 import org.oppia.android.app.devoptions.DeveloperOptionsStarterModule
 import org.oppia.android.app.model.CustomSchemaValue
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams
-import org.oppia.android.app.model.InputInteractionViewTestActivityParams.MathInteractionType
 import org.oppia.android.app.model.Interaction
+import org.oppia.android.app.model.MathExpressionInteractionsViewTestActivityParams
+import org.oppia.android.app.model.MathExpressionInteractionsViewTestActivityParams.MathInteractionType
 import org.oppia.android.app.model.OppiaLanguage
 import org.oppia.android.app.model.SchemaObject
 import org.oppia.android.app.model.SchemaObjectList
@@ -44,7 +46,7 @@ import org.oppia.android.app.player.state.answerhandling.AnswerErrorCategory.REA
 import org.oppia.android.app.player.state.answerhandling.AnswerErrorCategory.SUBMIT_TIME
 import org.oppia.android.app.player.state.itemviewmodel.SplitScreenInteractionModule
 import org.oppia.android.app.shim.ViewBindingShimModule
-import org.oppia.android.app.testing.InputInteractionViewTestActivity
+import org.oppia.android.app.testing.MathExpressionInteractionsViewTestActivity
 import org.oppia.android.app.translation.testing.ActivityRecreatorTestModule
 import org.oppia.android.data.backends.gae.NetworkConfigProdModule
 import org.oppia.android.data.backends.gae.NetworkModule
@@ -257,6 +259,63 @@ class MathExpressionInteractionsViewTest {
     }
   }
 
+  @Test
+  fun testNumericExpression_submitWithBlankInput_emptyInputErrorIsDisplayed() {
+    val interaction = createInteractionWithPlaceholder("test placeholder")
+    launchForNumericExpressions(interaction).use { scenario ->
+      testCoroutineDispatchers.runCurrent()
+      scenario.onActivity { activity -> activity.getInteractionView().requestFocus() }
+      testCoroutineDispatchers.runCurrent()
+      onView(withId(R.id.submit_button)).perform(click())
+      onView(withId(R.id.math_expression_input_error))
+        .check(
+          matches(
+            withText(
+              R.string.numeric_expression_error_empty_input
+            )
+          )
+        )
+    }
+  }
+
+  @Test
+  fun testAlgebraicExpression_submitWithBlankInput_emptyInputErrorIsDisplayed() {
+    val interaction = createInteractionWithPlaceholder("test placeholder")
+    launchForAlgebraicExpressions(interaction).use { scenario ->
+      testCoroutineDispatchers.runCurrent()
+      scenario.onActivity { activity -> activity.getInteractionView().requestFocus() }
+      testCoroutineDispatchers.runCurrent()
+      onView(withId(R.id.submit_button)).perform(click())
+      onView(withId(R.id.math_expression_input_error))
+        .check(
+          matches(
+            withText(
+              R.string.algebraic_expression_error_empty_input
+            )
+          )
+        )
+    }
+  }
+
+  @Test
+  fun testMathEquation_submitWithBlankInput_emptyInputErrorIsDisplayed() {
+    val interaction = createInteractionWithPlaceholder("test placeholder")
+    launchForMathEquations(interaction).use { scenario ->
+      testCoroutineDispatchers.runCurrent()
+      scenario.onActivity { activity -> activity.getInteractionView().requestFocus() }
+      testCoroutineDispatchers.runCurrent()
+      onView(withId(R.id.submit_button)).perform(click())
+      onView(withId(R.id.math_expression_input_error))
+        .check(
+          matches(
+            withText(
+              R.string.math_equation_error_empty_input
+            )
+          )
+        )
+    }
+  }
+
   @Test
   fun testView_gainFocus_resetsTypeFace() {
     launchForNumericExpressions().use { scenario ->
@@ -1602,6 +1661,28 @@ class MathExpressionInteractionsViewTest {
     }
   }
 
+  @Test
+  @RunParameterized(
+    Iteration("numeric_expression", "type=NUMERIC_EXPRESSION", "text="),
+    Iteration("algebraic_expression", "type=ALGEBRAIC_EXPRESSION", "text="),
+    Iteration("math_equation", "type=MATH_EQUATION", "text=")
+  )
+  fun testView_allInteractions_blankInput_produceSubmitTimeError() {
+    val interactionType = MathInteractionType.valueOf(type)
+    val interaction = createInteraction()
+    launch(interactionType, interaction).use { scenario ->
+      testCoroutineDispatchers.runCurrent()
+
+      typeExpressionInput(text)
+
+      // Using not-allowed-listed variables should result in a failure.
+      scenario.onActivity { activity ->
+        val answerError = activity.mathExpressionViewModel.checkPendingAnswerError(SUBMIT_TIME)
+        assertThat(answerError).isNotEmpty()
+      }
+    }
+  }
+
   @Test
   @RunParameterized(
     Iteration("numeric_expression_valid", "type=NUMERIC_EXPRESSION", "text=0/1"),
@@ -1630,26 +1711,33 @@ class MathExpressionInteractionsViewTest {
   private fun launchForNumericExpressions(
     interaction: Interaction = Interaction.getDefaultInstance(),
     translationContext: WrittenTranslationContext = WrittenTranslationContext.getDefaultInstance()
-  ): ActivityScenario<InputInteractionViewTestActivity> {
+  ): ActivityScenario<MathExpressionInteractionsViewTestActivity> {
     return launch(MathInteractionType.NUMERIC_EXPRESSION, interaction, translationContext)
   }
 
   private fun launchForMathEquations(
     interaction: Interaction = Interaction.getDefaultInstance(),
     translationContext: WrittenTranslationContext = WrittenTranslationContext.getDefaultInstance()
-  ): ActivityScenario<InputInteractionViewTestActivity> {
+  ): ActivityScenario<MathExpressionInteractionsViewTestActivity> {
     return launch(MathInteractionType.MATH_EQUATION, interaction, translationContext)
   }
 
+  private fun launchForAlgebraicExpressions(
+    interaction: Interaction = Interaction.getDefaultInstance(),
+    translationContext: WrittenTranslationContext = WrittenTranslationContext.getDefaultInstance()
+  ): ActivityScenario<MathExpressionInteractionsViewTestActivity> {
+    return launch(MathInteractionType.ALGEBRAIC_EXPRESSION, interaction, translationContext)
+  }
+
   private fun launch(
     interactionType: MathInteractionType,
     interaction: Interaction = Interaction.getDefaultInstance(),
     translationContext: WrittenTranslationContext = WrittenTranslationContext.getDefaultInstance()
-  ): ActivityScenario<InputInteractionViewTestActivity> {
+  ): ActivityScenario<MathExpressionInteractionsViewTestActivity> {
     return ActivityScenario.launch(
-      InputInteractionViewTestActivity.createIntent(
+      MathExpressionInteractionsViewTestActivity.createIntent(
         ApplicationProvider.getApplicationContext(),
-        InputInteractionViewTestActivityParams.newBuilder().apply {
+        MathExpressionInteractionsViewTestActivityParams.newBuilder().apply {
           this.interaction = interaction
           writtenTranslationContext = translationContext
           mathInteractionType = interactionType
@@ -1746,7 +1834,7 @@ class MathExpressionInteractionsViewTest {
     }.build()
   }
 
-  private fun InputInteractionViewTestActivity.getInteractionView(): TextView =
+  private fun MathExpressionInteractionsViewTestActivity.getInteractionView(): TextView =
     findViewById(R.id.test_math_expression_input_interaction_view)
 
   private fun setUpTestApplicationComponent() {
diff --git a/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt b/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
index 24193e64a33..d6a15aa0e00 100644
--- a/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
+++ b/app/src/sharedTest/java/org/oppia/android/app/player/state/StateFragmentTest.kt
@@ -2738,7 +2738,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("no reordering allowed")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -2754,7 +2754,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("no reordering allowed")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -2770,7 +2770,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("no reordering allowed")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -2822,7 +2822,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -2839,7 +2839,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -2909,7 +2909,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(NUMERIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3076,7 +3076,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("represents the product of")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3093,7 +3093,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("represents the product of")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3110,7 +3110,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("represents the product of")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3162,7 +3162,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3179,7 +3179,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3250,7 +3250,7 @@ class StateFragmentTest {
       // values being different.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3286,7 +3286,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(ALGEBRAIC_EXPRESSION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3467,7 +3467,7 @@ class StateFragmentTest {
       // matters for this interaction).
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("algebraic equation represents the quantity")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3484,7 +3484,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("algebraic equation represents the quantity")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3501,7 +3501,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("algebraic equation represents the quantity")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3518,7 +3518,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("algebraic equation represents the quantity")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3553,7 +3553,7 @@ class StateFragmentTest {
       // matters for this interaction).
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3588,7 +3588,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3605,7 +3605,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("commutative and associative")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3702,7 +3702,7 @@ class StateFragmentTest {
       // values being different.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3761,7 +3761,7 @@ class StateFragmentTest {
       // verify that the two sides are multiples of each other).
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
@@ -3778,7 +3778,7 @@ class StateFragmentTest {
       // Verify that the state hasn't changed since the answer is incorrect.
       verifyViewTypeIsPresent(MATH_EQUATION_INPUT_INTERACTION)
       verifyContentContains("any equivalent expression")
-      verifySubmitAnswerButtonIsDisabled()
+      verifySubmitAnswerButtonIsEnabled() // Wrong answers shouldn't disable submit.
     }
   }
 
diff --git a/model/src/main/proto/arguments.proto b/model/src/main/proto/arguments.proto
index 35b7278d833..614069ab4fa 100644
--- a/model/src/main/proto/arguments.proto
+++ b/model/src/main/proto/arguments.proto
@@ -46,6 +46,18 @@ message InputInteractionViewTestActivityParams {
   // Corresponds to the translation context which may affect the interaction's classifiers during
   // tests.
   WrittenTranslationContext written_translation_context = 2;
+}
+
+// TODO(#59): Isolate this to a test-only proto once possible.
+// Represents the parameters needed to open MathExpressionInteractionsViewTestActivity.
+message MathExpressionInteractionsViewTestActivityParams {
+  // Corresponds to the interaction used to initialize the interaction's view in the test
+  // environment.
+  Interaction interaction = 1;
+
+  // Corresponds to the translation context which may affect the interaction's classifiers during
+  // tests.
+  WrittenTranslationContext written_translation_context = 2;
 
   // Indicates that a math interaction should be displayed for this activity, and indicates which
   // one is being used in tests.
diff --git a/scripts/assets/accessibility_label_exemptions.textproto b/scripts/assets/accessibility_label_exemptions.textproto
index 34ac4cf6b1f..2ff301e7c53 100644
--- a/scripts/assets/accessibility_label_exemptions.textproto
+++ b/scripts/assets/accessibility_label_exemptions.textproto
@@ -27,6 +27,7 @@ exempted_activity: "app/src/main/java/org/oppia/android/app/testing/RatioInputIn
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/LessonThumbnailImageViewTestActivity"
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/ListItemLeadingMarginSpanTestActivity"
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/MarginBindingAdaptersTestActivity"
+exempted_activity: "app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity"
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/NavigationDrawerTestActivity"
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/PoliciesFragmentTestActivity"
 exempted_activity: "app/src/main/java/org/oppia/android/app/testing/ProfileChooserFragmentTestActivity"
diff --git a/scripts/assets/test_file_exemptions.textproto b/scripts/assets/test_file_exemptions.textproto
index 8a58df32b31..ee5df60d570 100644
--- a/scripts/assets/test_file_exemptions.textproto
+++ b/scripts/assets/test_file_exemptions.textproto
@@ -13,6 +13,7 @@ exempted_file_path: "app/src/main/java/org/oppia/android/app/administratorcontro
 exempted_file_path: "app/src/main/java/org/oppia/android/app/administratorcontrols/AdministratorControlsFragmentPresenter.kt"
 exempted_file_path: "app/src/main/java/org/oppia/android/app/testing/AdministratorControlsFragmentTestActivity.kt"
 exempted_file_path: "app/src/main/java/org/oppia/android/app/testing/AdministratorControlsFragmentTestActivityPresenter.kt"
+exempted_file_path: "app/src/main/java/org/oppia/android/app/testing/MathExpressionInteractionsViewTestActivity.kt"
 exempted_file_path: "app/src/main/java/org/oppia/android/app/administratorcontrols/AdministratorControlsViewModel.kt"
 exempted_file_path: "app/src/main/java/org/oppia/android/app/administratorcontrols/LoadAppVersionListener.kt"
 exempted_file_path: "app/src/main/java/org/oppia/android/app/administratorcontrols/LoadLearnerAnalyticsListener.kt"