1 files changed, 48 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/matchers_spec.js b/spec/frontend/__helpers__/matchers_spec.js
new file mode 100644
index 00000000000..dfd6f754c72
--- /dev/null
+++ b/spec/frontend/__helpers__/matchers_spec.js
@@ -0,0 +1,48 @@
+describe('Custom jest matchers', () => {
+  describe('toMatchInterpolatedText', () => {
+    describe('malformed input', () => {
+      it.each([null, 1, Symbol, Array, Object])(
+        'fails graciously if the expected value is %s',
+        (expected) => {
+          expect(expected).not.toMatchInterpolatedText('null');
+        },
+      );
+    });
+    describe('malformed matcher', () => {
+      it.each([null, 1, Symbol, Array, Object])(
+        'fails graciously if the matcher is %s',
+        (matcher) => {
+          expect('null').not.toMatchInterpolatedText(matcher);
+        },
+      );
+    });
+
+    describe('positive assertion', () => {
+      it.each`
+        htmlString         | templateString
+        ${'foo'}           | ${'foo'}
+        ${'foo'}           | ${'foo%{foo}'}
+        ${'foo  '}         | ${'foo'}
+        ${'foo  '}         | ${'foo%{foo}'}
+        ${'foo   . '}      | ${'foo%{foo}.'}
+        ${'foo   bar . '}  | ${'foo%{foo} bar.'}
+        ${'foo\n\nbar . '} | ${'foo%{foo} bar.'}
+        ${'foo bar . .'}   | ${'foo%{fooStart} bar.%{fooEnd}.'}
+      `('$htmlString equals $templateString', ({ htmlString, templateString }) => {
+        expect(htmlString).toMatchInterpolatedText(templateString);
+      });
+    });
+
+    describe('negative assertion', () => {
+      it.each`
+        htmlString  | templateString
+        ${'foo'}    | ${'bar'}
+        ${'foo'}    | ${'bar%{foo}'}
+        ${'foo'}    | ${'@{lol}foo%{foo}'}
+        ${' fo o '} | ${'foo'}
+      `('$htmlString does not equal $templateString', ({ htmlString, templateString }) => {
+        expect(htmlString).not.toMatchInterpolatedText(templateString);
+      });
+    });
+  });
+});