Support stubbing of the ENV variable

CHANGELOG.md

@@ -5,6 +5,23 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## Not released
+
+### Added
+
+- Support for stubbing ENV variables (nepalez)
+
+```yaml
+---
+- env: GOOGLE_CLOUD_KEY
+  value: foo
+
+- env: GOOGLE_CLOUD_PASSWORD
+  value: bar
+```
+
+This would stub selected variables only, not touching the others
+
 ## [0.3.0] - [2020-03-08]
 
 ### Added

README.md

@@ -141,6 +141,11 @@ For constants:
 - `const` for stubbed constant
 - `value` for a value of the constant
 
+For environment variables:
+
+- `env` for the name of a variable
+  `value` for a value of the variable
+
 For http requests:
 
 - `url` or `uri` for the URI of the request (treats values like `/.../` as regular expressions)
@@ -186,9 +191,14 @@ For http requests:
       arguments:
         - "Profile with id: 1 not found" # for error message
 
+# Here we stubbing a constant
 - const: NOTIFIER_TIMEOUT_SEC
   value: 10
 
+# This is a stub for ENV['DEFAULT_EMAIL']
+- env: DEFAULT_EMAIL
+  value: [email protected]
+
 # Examples for stubbing HTTP
 - uri: /example.com/foo/ # regexp!
   method: delete

lib/fixturama/changes.rb

@@ -7,6 +7,7 @@ class Changes
     require_relative "changes/base"
     require_relative "changes/chain"
     require_relative "changes/const"
+    require_relative "changes/env"
     require_relative "changes/request"
     require_relative "changes/seed"
 
@@ -20,6 +21,7 @@ class Changes
       class: Chain,
       const: Const,
       count: Seed,
+      env: Env,
       headers: Request,
       http_method: Request,
       object: Chain,
@@ -31,7 +33,6 @@ class Changes
       type: Seed,
       uri: Request,
       url: Request,
-      value: Const,
     }.freeze
 
     # Adds new change to the registry

lib/fixturama/changes/env.rb

@@ -0,0 +1,35 @@
+class Fixturama::Changes
+  #
+  # @private
+  # Stub an environment variable
+  #
+  class Env < Base
+    # All changes has the same +key+
+    # They will be merged before stubbing (see +call+)
+    def key
+      "ENV"
+    end
+
+    # When we merge 2 env-s, we just merge their options
+    def merge(other)
+      return self unless other.is_a?(self.class)
+      dup.tap { |env| env.options.update(other.options) }
+    end
+
+    def call(example)
+      original = Hash ENV
+      example.send(:stub_const, "ENV", original.merge(options))
+      self
+    end
+
+    protected
+
+    attr_reader :options
+
+    private
+
+    def initialize(**options)
+      @options = { options[:env].to_s => options[:value].to_s }
+    end
+  end
+end

lib/fixturama/version.rb

@@ -1,3 +1,4 @@
 module Fixturama
+  # The current version of the gem
   VERSION = "0.3.0"
 end

spec/fixturama/stub_fixture/_spec.rb

@@ -97,6 +97,24 @@ def pay(_)
     end
   end
 
+  context "when ENV stubbed" do
+    before do
+      ENV["FOO"] = "foo"
+      ENV["BAR"] = "bar"
+      ENV["QUX"] = "qux"
+      stub_fixture "#{__dir__}/stub.yml"
+    end
+
+    it "stubs the ENV" do
+      expect(ENV["FOO"]).to eq "oof"
+      expect(ENV["BAR"]).to eq "rab"
+    end
+
+    it "preserves unstubbed ENV" do
+      expect(ENV["QUX"]).to eq "qux"
+    end
+  end
+
   context "when http request stubbed" do
     before { stub_fixture "#{__dir__}/stub.yml" }
 

spec/fixturama/stub_fixture/stub.yml

@@ -73,3 +73,9 @@
   responses:
     - status: 200
     - status: 404 # for any request except for the first one
+
+- env: FOO
+  value: oof
+
+- env: BAR
+  value: rab