1 files changed, 35 insertions, 0 deletions
diff --git a/spec/frontend/__helpers__/matchers/to_have_tracking_attributes.js b/spec/frontend/__helpers__/matchers/to_have_tracking_attributes.js
new file mode 100644
index 00000000000..fd3f3aa042f
--- /dev/null
+++ b/spec/frontend/__helpers__/matchers/to_have_tracking_attributes.js
@@ -0,0 +1,35 @@
+import { diff } from 'jest-diff';
+import { isObject, mapValues, isEqual } from 'lodash';
+
+export const toHaveTrackingAttributes = (actual, obj) => {
+  if (!(actual instanceof Element)) {
+    return { actual, message: () => 'The received value must be an Element.', pass: false };
+  }
+
+  if (!isObject(obj)) {
+    return {
+      message: () => `The matching object must be an object. Found ${obj}.`,
+      pass: false,
+    };
+  }
+
+  const actualAttributes = mapValues(obj, (val, key) => actual.getAttribute(`data-track-${key}`));
+
+  const matcherPass = isEqual(actualAttributes, obj);
+
+  const failMessage = () => {
+    // We can match, but still fail because we're in a `expect...not.` context
+    if (matcherPass) {
+      return `Expected the element's tracking attributes not to match. Found that they matched ${JSON.stringify(
+        obj,
+      )}.`;
+    }
+
+    const objDiff = diff(actualAttributes, obj);
+    return `Expected the element's tracking attributes to match the given object. Diff:
+${objDiff}
+`;
+  };
+
+  return { actual, message: failMessage, pass: matcherPass };
+};