Add a `Blob` model that wraps `Gitlab::Git::Blob`rs-blob

This allows us to take advantage of Rails' `to_partial_path` to render
the correct partial based on the Blob type, rather than cluttering the
view with conditionals.

It also allows (and will allow in the future) better encapsulation for
Blob-related logic which makes sense for our Rails app but might not
make as much sense for the core `gitlab_git` library, such as detecting
if the blob is an SVG.

1 files changed, 81 insertions, 0 deletions

diff --git a/spec/models/blob_spec.rb b/spec/models/blob_spec.rb
new file mode 100644
index 00000000000..78e95c8fac5
--- /dev/null
+++ b/spec/models/blob_spec.rb
@@ -0,0 +1,81 @@
+require 'rails_helper'
+
+describe Blob do
+  describe '.decorate' do
+    it 'returns NilClass when given nil' do
+      expect(described_class.decorate(nil)).to be_nil
+    end
+  end
+
+  describe '#svg?' do
+    it 'is falsey when not text' do
+      git_blob = double(text?: false)
+
+      expect(described_class.decorate(git_blob)).not_to be_svg
+    end
+
+    it 'is falsey when no language is detected' do
+      git_blob = double(text?: true, language: nil)
+
+      expect(described_class.decorate(git_blob)).not_to be_svg
+    end
+
+    it' is falsey when language is not SVG' do
+      git_blob = double(text?: true, language: double(name: 'XML'))
+
+      expect(described_class.decorate(git_blob)).not_to be_svg
+    end
+
+    it 'is truthy when language is SVG' do
+      git_blob = double(text?: true, language: double(name: 'SVG'))
+
+      expect(described_class.decorate(git_blob)).to be_svg
+    end
+  end
+
+  describe '#to_partial_path' do
+    def stubbed_blob(overrides = {})
+      overrides.reverse_merge!(
+        image?: false,
+        language: nil,
+        lfs_pointer?: false,
+        svg?: false,
+        text?: false
+      )
+
+      described_class.decorate(double).tap do |blob|
+        allow(blob).to receive_messages(overrides)
+      end
+    end
+
+    it 'handles LFS pointers' do
+      blob = stubbed_blob(lfs_pointer?: true)
+
+      expect(blob.to_partial_path).to eq 'download'
+    end
+
+    it 'handles SVGs' do
+      blob = stubbed_blob(text?: true, svg?: true)
+
+      expect(blob.to_partial_path).to eq 'image'
+    end
+
+    it 'handles images' do
+      blob = stubbed_blob(image?: true)
+
+      expect(blob.to_partial_path).to eq 'image'
+    end
+
+    it 'handles text' do
+      blob = stubbed_blob(text?: true)
+
+      expect(blob.to_partial_path).to eq 'text'
+    end
+
+    it 'defaults to download' do
+      blob = stubbed_blob
+
+      expect(blob.to_partial_path).to eq 'download'
+    end
+  end
+end