1 files changed, 105 insertions, 0 deletions
diff --git a/spec/frontend/lib/utils/yaml_spec.js b/spec/frontend/lib/utils/yaml_spec.js
new file mode 100644
index 00000000000..d1ce00130e2
--- /dev/null
+++ b/spec/frontend/lib/utils/yaml_spec.js
@@ -0,0 +1,105 @@
+import { Document, parseDocument } from 'yaml';
+import { merge } from '~/lib/utils/yaml';
+
+// Mock data for Comments on pairs
+const COMMENTS_ON_PAIRS_SOURCE = `foo:
+  # barbaz
+  bar: baz
+
+  # bazboo
+  baz: boo
+`;
+
+const COMMENTS_ON_PAIRS_TARGET = `foo:
+  # abcdef
+  abc: def
+  # boobaz
+  boo: baz
+`;
+
+const COMMENTS_ON_PAIRS_EXPECTED = `foo:
+  # abcdef
+  abc: def
+  # boobaz
+  boo: baz
+  # barbaz
+  bar: baz
+
+  # bazboo
+  baz: boo
+`;
+
+// Mock data for Comments on seqs
+const COMMENTS_ON_SEQS_SOURCE = `foo:
+  # barbaz
+  - barbaz
+  # bazboo
+  - baz: boo
+`;
+
+const COMMENTS_ON_SEQS_TARGET = `foo:
+  # abcdef
+  - abcdef
+
+  # boobaz
+  - boobaz
+`;
+
+const COMMENTS_ON_SEQS_EXPECTED = `foo:
+  # abcdef
+  - abcdef
+
+  # boobaz
+  - boobaz
+  # barbaz
+  - barbaz
+  # bazboo
+  - baz: boo
+`;
+
+describe('Yaml utility functions', () => {
+  describe('merge', () => {
+    const getAsNode = (yamlStr) => {
+      return parseDocument(yamlStr).contents;
+    };
+
+    describe('Merge two Nodes', () => {
+      it.each`
+        scenario                               | source                                       | target                                         | options                      | expected
+        ${'merge a map'}                       | ${getAsNode('foo:\n  bar: baz\n')}           | ${'foo:\n  abc: def\n'}                        | ${undefined}                 | ${'foo:\n  abc: def\n  bar: baz\n'}
+        ${'merge a seq'}                       | ${getAsNode('foo:\n  - bar\n')}              | ${'foo:\n  - abc\n'}                           | ${undefined}                 | ${'foo:\n  - bar\n'}
+        ${'merge-append seqs'}                 | ${getAsNode('foo:\n  - bar\n')}              | ${'foo:\n  - abc\n'}                           | ${{ onSequence: 'append' }}  | ${'foo:\n  - abc\n  - bar\n'}
+        ${'merge-replace a seq'}               | ${getAsNode('foo:\n  - bar\n')}              | ${'foo:\n  - abc\n'}                           | ${{ onSequence: 'replace' }} | ${'foo:\n  - bar\n'}
+        ${'override existing paths'}           | ${getAsNode('foo:\n  bar: baz\n')}           | ${'foo:\n  bar: boo\n'}                        | ${undefined}                 | ${'foo:\n  bar: baz\n'}
+        ${'deep maps'}                         | ${getAsNode('foo:\n  bar:\n    abc: def\n')} | ${'foo:\n  bar:\n    baz: boo\n  jkl:  mno\n'} | ${undefined}                 | ${'foo:\n  bar:\n    baz: boo\n    abc: def\n  jkl: mno\n'}
+        ${'append maps inside seqs'}           | ${getAsNode('foo:\n  - abc: def\n')}         | ${'foo:\n  - bar: baz\n'}                      | ${{ onSequence: 'append' }}  | ${'foo:\n  - bar: baz\n  - abc: def\n'}
+        ${'inexistent paths create new nodes'} | ${getAsNode('foo:\n  bar: baz\n')}           | ${'abc: def\n'}                                | ${undefined}                 | ${'abc: def\nfoo:\n  bar: baz\n'}
+        ${'document as source'}                | ${parseDocument('foo:\n  bar: baz\n')}       | ${'foo:\n  abc: def\n'}                        | ${undefined}                 | ${'foo:\n  abc: def\n  bar: baz\n'}
+        ${'object as source'}                  | ${{ foo: { bar: 'baz' } }}                   | ${'foo:\n  abc: def\n'}                        | ${undefined}                 | ${'foo:\n  abc: def\n  bar: baz\n'}
+        ${'comments on pairs'}                 | ${parseDocument(COMMENTS_ON_PAIRS_SOURCE)}   | ${COMMENTS_ON_PAIRS_TARGET}                    | ${undefined}                 | ${COMMENTS_ON_PAIRS_EXPECTED}
+        ${'comments on seqs'}                  | ${parseDocument(COMMENTS_ON_SEQS_SOURCE)}    | ${COMMENTS_ON_SEQS_TARGET}                     | ${{ onSequence: 'append' }}  | ${COMMENTS_ON_SEQS_EXPECTED}
+      `('$scenario', ({ source, target, expected, options }) => {
+        const targetDoc = parseDocument(target);
+        merge(targetDoc, source, options);
+        const expectedDoc = parseDocument(expected);
+        expect(targetDoc.toString()).toEqual(expectedDoc.toString());
+      });
+
+      it('type conflict will throw an Error', () => {
+        const sourceDoc = parseDocument('foo:\n  bar:\n    - baz\n');
+        const targetDoc = parseDocument('foo:\n  bar: def\n');
+        expect(() => merge(targetDoc, sourceDoc)).toThrow(
+          'Type conflict at "foo.bar": Destination node is of type Scalar, the node' +
+            ' to be merged is of type YAMLSeq',
+        );
+      });
+
+      it('merging a collection into an empty doc', () => {
+        const targetDoc = new Document();
+        merge(targetDoc, { foo: { bar: 'baz' } });
+        const expected = parseDocument('foo:\n  bar: baz\n');
+        expect(targetDoc.toString()).toEqual(expected.toString());
+      });
+    });
+  });
+});