GUILD-619: Test helpers don't automatically reset to test config

CHANGELOG.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## UNRELEASED
+### Roadmap :car:
+
+- TestHelper does not automatically reset Deimos config before each test. [#120](https://github.com/flipp-oss/deimos/pull/120)
 
 ## 1.10.0 - 2021-03-22
 

README.md

@@ -29,6 +29,7 @@ Built on Phobos and hence Ruby-Kafka.
    * [Running Consumers](#running-consumers)
    * [Metrics](#metrics)
    * [Testing](#testing)
+        * [Default Deimos config for testing](#default-deimos-config-for-testing)
         * [Integration Test Helpers](#integration-test-helpers)
    * [Utilities](#utilities)
    * [Contributing](#contributing) 
@@ -935,6 +936,18 @@ expect(message).to eq({
   topic: 'my-topic',
   key: 'my-id'
 })
+
+## Configuring Deimos to test settings
+
+# You can reset Deimos to default test config by calling this method.
+configure_deimos
+
+# The same method can be used to override settings while still using
+# deafults for other fields.
+configure_deimos(consumers: { reraise_errors: false },
+                 producers: { topic_prefix: nil },
+                 db_producer: { compact_topics: %w(my-topic my-topic2) },
+                 logger: Rails.logger)
 ```
 
 There is also a helper method that will let you test if an existing schema
@@ -946,6 +959,28 @@ require 'deimos/test_helpers'
 # Can pass a file path, a string or a hash into this:
 Deimos::TestHelpers.schemas_compatible?(schema1, schema2)
 ```
+### Default Deimos config for testing
+
+The test helper class provides the default settings for Deimos config.
+```ruby
+# The following are the test defaults for Deimos that are set
+# by calling `configure_deimos` 
+DEFAULT_TEST_CONFIG = {
+  logger: Logger.new(STDOUT),
+  consumers: { reraise_errors: true },
+  kafka: { seed_brokers: ['test_broker'] },
+  schema: { backend: Deimos.schema_backend_class.mock_backend },
+  producers: { backend: :test }
+}
+```
+`:test` is the default backend for producers that saves messages
+to an in-memory hash. You can access the sent messages by calling 
+the following function
+```ruby
+Deimos::Backends::Test.sent_messages
+```
+Mock schema backend will perform all the validations but not actually encode any messages.
+
 
 ### Integration Test Helpers
 

lib/deimos/test_helpers.rb

@@ -18,22 +18,31 @@ class << self
       def sent_messages
         Deimos::Backends::Test.sent_messages
       end
+
+      # Set the config to the right settings for a unit test
+      def unit_test!
+        Deimos.configure do |deimos_config|
+          deimos_config.logger = Logger.new(STDOUT)
+          deimos_config.consumers.reraise_errors = true
+          deimos_config.kafka.seed_brokers ||= ['test_broker']
+          deimos_config.schema.backend = Deimos.schema_backend_class.mock_backend
+          deimos_config.producers.backend = :test
+        end
+      end
+
+      # Set the config to the right settings for a kafka test
+      def kafka_test!
+        Deimos.configure do |deimos_config|
+          deimos_config.producers.backend = :kafka
+          deimos_config.schema.backend = :avro_validation
+        end
+      end
     end
 
     included do
 
       RSpec.configure do |config|
 
-        config.before(:suite) do
-          Deimos.configure do |d_config|
-            d_config.logger = Logger.new(STDOUT)
-            d_config.consumers.reraise_errors = true
-            d_config.kafka.seed_brokers ||= ['test_broker']
-            d_config.schema.backend = Deimos.schema_backend_class.mock_backend
-            d_config.producers.backend = :test
-          end
-        end
-
         config.prepend_before(:each) do
           client = double('client').as_null_object
           allow(client).to receive(:time) do |*_args, &block|