Merge branch 'feature/test-coverage-badge' into 'master'

Add test coverage badge

## What does this MR do?

This MR adds a test coverage badge.

Test coverage badge will be a SVG image you can embed in README.md or on your website that will be created dynamically by GitLab, to show information about how much of the code is being covered by tests. In addition to coverage-regexp feature we currently have, this feature will make it possible to use the coverage data obtained from the build log. We will support both - pipeline coverage, or test coverage for particular job in the pipeline. 

![coverage_badges](/uploads/dfa307339eb58c8138e551b42c0d8756/coverage_badges.png)

![coverage_badge](/uploads/30406e4bdcf979b2900ffe8996728c97/coverage_badge.png)

## What are the relevant issue numbers?

Closes #3714

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5708

10 files changed, 296 insertions, 69 deletions

diff --git a/lib/gitlab/badge/base.rb b/lib/gitlab/badge/base.rb
new file mode 100644
index 00000000000..909fa24fa90
--- /dev/null
+++ b/lib/gitlab/badge/base.rb
@@ -0,0 +1,21 @@
+module Gitlab
+  module Badge
+    class Base
+      def entity
+        raise NotImplementedError
+      end
+
+      def status
+        raise NotImplementedError
+      end
+
+      def metadata
+        raise NotImplementedError
+      end
+
+      def template
+        raise NotImplementedError
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/build.rb b/lib/gitlab/badge/build.rb
deleted file mode 100644
index 1de721a2269..00000000000
--- a/lib/gitlab/badge/build.rb
+++ /dev/null
@@ -1,30 +0,0 @@
-module Gitlab
-  module Badge
-    ##
-    # Build badge
-    #
-    class Build
-      delegate :key_text, :value_text, to: :template
-
-      def initialize(project, ref)
-        @project = project
-        @ref = ref
-        @sha = @project.commit(@ref).try(:sha)
-      end
-
-      def status
-        @project.pipelines
-          .where(sha: @sha, ref: @ref)
-          .status || 'unknown'
-      end
-
-      def metadata
-        @metadata ||= Build::Metadata.new(@project, @ref)
-      end
-
-      def template
-        @template ||= Build::Template.new(status)
-      end
-    end
-  end
-end
diff --git a/lib/gitlab/badge/build/metadata.rb b/lib/gitlab/badge/build/metadata.rb
index 553ef8d7b16..f87a7b7942e 100644
--- a/lib/gitlab/badge/build/metadata.rb
+++ b/lib/gitlab/badge/build/metadata.rb
@@ -1,25 +1,17 @@
 module Gitlab
   module Badge
-    class Build
+    module Build
       ##
       # Class that describes build badge metadata
       #
-      class Metadata
-        include Gitlab::Application.routes.url_helpers
-        include ActionView::Helpers::AssetTagHelper
-        include ActionView::Helpers::UrlHelper
-
-        def initialize(project, ref)
-          @project = project
-          @ref = ref
-        end
-
-        def to_html
-          link_to(image_tag(image_url, alt: 'build status'), link_url)
+      class Metadata < Badge::Metadata
+        def initialize(badge)
+          @project = badge.project
+          @ref = badge.ref
         end
 
-        def to_markdown
-          "[![build status](#{image_url})](#{link_url})"
+        def title
+          'build status'
         end
 
         def image_url
diff --git a/lib/gitlab/badge/build/status.rb b/lib/gitlab/badge/build/status.rb
new file mode 100644
index 00000000000..50aa45e5406
--- /dev/null
+++ b/lib/gitlab/badge/build/status.rb
@@ -0,0 +1,37 @@
+module Gitlab
+  module Badge
+    module Build
+      ##
+      # Build status badge
+      #
+      class Status < Badge::Base
+        attr_reader :project, :ref
+
+        def initialize(project, ref)
+          @project = project
+          @ref = ref
+
+          @sha = @project.commit(@ref).try(:sha)
+        end
+
+        def entity
+          'build'
+        end
+
+        def status
+          @project.pipelines
+            .where(sha: @sha, ref: @ref)
+            .status || 'unknown'
+        end
+
+        def metadata
+          @metadata ||= Build::Metadata.new(self)
+        end
+
+        def template
+          @template ||= Build::Template.new(self)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/build/template.rb b/lib/gitlab/badge/build/template.rb
index deba3b669b3..2b95ddfcb53 100644
--- a/lib/gitlab/badge/build/template.rb
+++ b/lib/gitlab/badge/build/template.rb
@@ -1,12 +1,12 @@
 module Gitlab
   module Badge
-    class Build
+    module Build
       ##
       # Class that represents a build badge template.
       #
       # Template object will be passed to badge.svg.erb template.
       #
-      class Template
+      class Template < Badge::Template
         STATUS_COLOR = {
           success: '#4c1',
           failed: '#e05d44',
@@ -17,16 +17,17 @@ module Gitlab
           unknown: '#9f9f9f'
         }
 
-        def initialize(status)
-          @status = status
+        def initialize(badge)
+          @entity = badge.entity
+          @status = badge.status
         end
 
         def key_text
-          'build'
+          @entity.to_s
         end
 
         def value_text
-          @status
+          @status.to_s
         end
 
         def key_width
@@ -37,25 +38,8 @@ module Gitlab
           54
         end
 
-        def key_color
-          '#555'
-        end
-
         def value_color
-          STATUS_COLOR[@status.to_sym] ||
-            STATUS_COLOR[:unknown]
-        end
-
-        def key_text_anchor
-          key_width / 2
-        end
-
-        def value_text_anchor
-          key_width + (value_width / 2)
-        end
-
-        def width
-          key_width + value_width
+          STATUS_COLOR[@status.to_sym] || STATUS_COLOR[:unknown]
         end
       end
     end
diff --git a/lib/gitlab/badge/coverage/metadata.rb b/lib/gitlab/badge/coverage/metadata.rb
new file mode 100644
index 00000000000..53588185622
--- /dev/null
+++ b/lib/gitlab/badge/coverage/metadata.rb
@@ -0,0 +1,30 @@
+module Gitlab
+  module Badge
+    module Coverage
+      ##
+      # Class that describes coverage badge metadata
+      #
+      class Metadata < Badge::Metadata
+        def initialize(badge)
+          @project = badge.project
+          @ref = badge.ref
+          @job = badge.job
+        end
+
+        def title
+          'coverage report'
+        end
+
+        def image_url
+          coverage_namespace_project_badges_url(@project.namespace,
+                                                @project, @ref,
+                                                format: :svg)
+        end
+
+        def link_url
+          namespace_project_commits_url(@project.namespace, @project, id: @ref)
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/coverage/report.rb b/lib/gitlab/badge/coverage/report.rb
new file mode 100644
index 00000000000..3d56ea3e47a
--- /dev/null
+++ b/lib/gitlab/badge/coverage/report.rb
@@ -0,0 +1,56 @@
+module Gitlab
+  module Badge
+    module Coverage
+      ##
+      # Test coverage report badge
+      #
+      class Report < Badge::Base
+        attr_reader :project, :ref, :job
+
+        def initialize(project, ref, job = nil)
+          @project = project
+          @ref = ref
+          @job = job
+
+          @pipeline = @project.pipelines
+            .where(ref: @ref)
+            .where(sha: @project.commit(@ref).try(:sha))
+            .first
+        end
+
+        def entity
+          'coverage'
+        end
+
+        def status
+          @coverage ||= raw_coverage
+          return unless @coverage
+
+          @coverage.to_i
+        end
+
+        def metadata
+          @metadata ||= Coverage::Metadata.new(self)
+        end
+
+        def template
+          @template ||= Coverage::Template.new(self)
+        end
+
+        private
+
+        def raw_coverage
+          return unless @pipeline
+
+          if @job.blank?
+            @pipeline.coverage
+          else
+            @pipeline.builds
+              .find_by(name: @job)
+              .try(:coverage)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/coverage/template.rb b/lib/gitlab/badge/coverage/template.rb
new file mode 100644
index 00000000000..06e0d084e9f
--- /dev/null
+++ b/lib/gitlab/badge/coverage/template.rb
@@ -0,0 +1,52 @@
+module Gitlab
+  module Badge
+    module Coverage
+      ##
+      # Class that represents a coverage badge template.
+      #
+      # Template object will be passed to badge.svg.erb template.
+      #
+      class Template < Badge::Template
+        STATUS_COLOR = {
+          good: '#4c1',
+          acceptable: '#a3c51c',
+          medium: '#dfb317',
+          low: '#e05d44',
+          unknown: '#9f9f9f'
+        }
+
+        def initialize(badge)
+          @entity = badge.entity
+          @status = badge.status
+        end
+
+        def key_text
+          @entity.to_s
+        end
+
+        def value_text
+          @status ? "#{@status}%" : 'unknown'
+        end
+
+        def key_width
+          62
+        end
+
+        def value_width
+          @status ? 36 : 58
+        end
+
+        def value_color
+          case @status
+          when 95..100 then STATUS_COLOR[:good]
+          when 90..95 then STATUS_COLOR[:acceptable]
+          when 75..90 then STATUS_COLOR[:medium]
+          when 0..75 then STATUS_COLOR[:low]
+          else
+            STATUS_COLOR[:unknown]
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/metadata.rb b/lib/gitlab/badge/metadata.rb
new file mode 100644
index 00000000000..548f85b78bb
--- /dev/null
+++ b/lib/gitlab/badge/metadata.rb
@@ -0,0 +1,36 @@
+module Gitlab
+  module Badge
+    ##
+    # Abstract class for badge metadata
+    #
+    class Metadata
+      include Gitlab::Application.routes.url_helpers
+      include ActionView::Helpers::AssetTagHelper
+      include ActionView::Helpers::UrlHelper
+
+      def initialize(badge)
+        @badge = badge
+      end
+
+      def to_html
+        link_to(image_tag(image_url, alt: title), link_url)
+      end
+
+      def to_markdown
+        "[![#{title}](#{image_url})](#{link_url})"
+      end
+
+      def title
+        raise NotImplementedError
+      end
+
+      def image_url
+        raise NotImplementedError
+      end
+
+      def link_url
+        raise NotImplementedError
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/badge/template.rb b/lib/gitlab/badge/template.rb
new file mode 100644
index 00000000000..bfeb0052642
--- /dev/null
+++ b/lib/gitlab/badge/template.rb
@@ -0,0 +1,49 @@
+module Gitlab
+  module Badge
+    ##
+    # Abstract template class for badges
+    #
+    class Template
+      def initialize(badge)
+        @entity = badge.entity
+        @status = badge.status
+      end
+
+      def key_text
+        raise NotImplementedError
+      end
+
+      def value_text
+        raise NotImplementedError
+      end
+
+      def key_width
+        raise NotImplementedError
+      end
+
+      def value_width
+        raise NotImplementedError
+      end
+
+      def value_color
+        raise NotImplementedError
+      end
+
+      def key_color
+        '#555'
+      end
+
+      def key_text_anchor
+        key_width / 2
+      end
+
+      def value_text_anchor
+        key_width + (value_width / 2)
+      end
+
+      def width
+        key_width + value_width
+      end
+    end
+  end
+end