chore: add docker image for development (pact-foundation#280)

* Refactor test to verify on general error case

- Duplicate cert error is already verified in Ruby spec
- Duplicate cert error does not always throw error
(ie. for OpenSSL < 1.1.1)

* Add Dockerfile for testing/development purposes

* Update developer setup doc

Author: tancnle

.dockerignore

@@ -0,0 +1,2 @@
+**/.git
+tmp

DEVELOPER_SETUP.md

@@ -1,35 +1,55 @@
 # Developer setup
 
+## Preparation
+
+### With virtual battery
+
+* Build an initial local image with Docker
+  ```sh
+  docker build --rm -t pact_broker:dev .
+  ```
+
+* Spin up a container with mounted volume and open an interactive shell session
+  ```sh
+  docker run --rm -v $(PWD):/app -w /app -it pact_broker:dev bash
+  ```
+
+### With native install
+
 * You will need to install Ruby 2.5, and preferably a ruby version manager. I recommend using [chruby][chruby] and [ruby-install][ruby-install].
 * Install bundler (the Ruby gem dependency manager) `gem install bundler`
 * Check out the pact_broker repository and cd into it.
 * Run `bundle install`. If you have not got mysql or postgres installed locally, comment out the `mysql2` and `pg` development dependency lines in `pact_broker.gemspec`, as these are only really required on Travis.
-* Run `bundle exec rake pact_broker:dev:setup`. This will create an example application that you can run locally, that uses the local source code.
-* To run the example:
 
-      cd dev
-      bundle install
-      bundle exec rackup
+## Running a local application
 
+* Run `bundle exec rake pact_broker:dev:setup`. This will create an example application that you can run locally, that uses the local source code.
+* To run the example:
+  ```sh
+  cd dev
+  bundle install
+  bundle exec rackup
+  ```
 * The application will be available on `http://localhost:9292`
 
 ## Running the tests
 
-To run everything (specs, pact verifications, vulnerability scan...):
-
-`bundle exec rake`
-
-To run a smaller subset of the tests:
-
-`bundle exec rake spec`
-
-To run the "quick tests" (skip the lengthy migration specs)
-
-`bundle exec rake spec:quick`
-
-To run a single spec:
-
-`bundle exec rspec path_to_your_spec.rb`
+* To run everything (specs, pact verifications, vulnerability scan...):
+  ```sh
+  bundle exec rake
+  ```
+* To run a smaller subset of the tests:
+  ```sh
+  bundle exec rake spec
+  ```
+* To run the "quick tests" (skip the lengthy migration specs)
+  ```sh
+  bundle exec rake spec:quick
+  ```
+* To run a single spec:
+  ```sh
+  bundle exec rspec path_to_your_spec.rb
+  ```
 
 [chruby]: https://github.com/postmodern/chruby
 [ruby-install]: https://github.com/postmodern/ruby-install

Dockerfile

@@ -0,0 +1,22 @@
+FROM ruby:2.5.3-alpine
+
+RUN apk update \
+    && apk --no-cache add \
+      "build-base>=0.5" \
+      "bash>=4.4" \
+      "ca-certificates>=20190108" \
+      "git>=2.20" \
+      "postgresql-dev>=11.3" \
+      "sqlite-dev>=3.28" \
+      "sqlite>=3.28" \
+      "tzdata>=2019" \
+    && rm -rf /var/cache/apk/*
+
+WORKDIR /app
+
+COPY . ./
+
+RUN gem install bundler -v '~>2.0.0' \
+    && bundle install --jobs 3 --retry 3
+
+CMD []

spec/lib/pact_broker/certificates/service_spec.rb

@@ -4,7 +4,7 @@ module PactBroker
   module Certificates
     describe Service do
       let(:certificate_content) { File.read('spec/fixtures/certificate.pem') }
-      let(:logger) { double('logger').as_null_object }
+      let(:logger) { spy('logger') }
 
       before do
         allow(Service).to receive(:logger).and_return(logger)
@@ -17,19 +17,25 @@ module Certificates
           expect(subject).to be_instance_of(OpenSSL::X509::Store)
         end
 
-        context "when there is a duplicate certificate" do
+        context "when there is an error adding certificate" do
+          let(:cert_store) { instance_spy(OpenSSL::X509::Store) }
+
           before do
             Certificate.create(uuid: '1234', content: certificate_content)
-            Certificate.create(uuid: '5678', content: certificate_content)
+
+            allow(cert_store).to receive(:add_cert).and_raise(StandardError)
+            allow(OpenSSL::X509::Store).to receive(:new).and_return(cert_store)
           end
 
           it "logs the error" do
-            expect(Service).to receive(:log_error).with(anything, /Error adding certificate/).at_least(1).times
             subject
+
+            expect(logger).to have_received(:error)
+              .with(/Error adding certificate/).at_least(1).times
           end
 
           it "returns an OpenSSL::X509::Store" do
-            expect(subject).to be_instance_of(OpenSSL::X509::Store)
+            expect(subject).to be(cert_store)
           end
         end
       end