1 files changed, 38 insertions, 0 deletions
diff --git a/spec/frontend/matchers.js b/spec/frontend/matchers.js
new file mode 100644
index 00000000000..35c362d0bf5
--- /dev/null
+++ b/spec/frontend/matchers.js
@@ -0,0 +1,38 @@
+export default {
+  toHaveSpriteIcon: (element, iconName) => {
+    if (!iconName) {
+      throw new Error('toHaveSpriteIcon is missing iconName argument!');
+    }
+
+    if (!(element instanceof HTMLElement)) {
+      throw new Error(`${element} is not a DOM element!`);
+    }
+
+    const iconReferences = [].slice.apply(element.querySelectorAll('svg use'));
+    const matchingIcon = iconReferences.find(reference =>
+      reference.getAttribute('xlink:href').endsWith(`#${iconName}`),
+    );
+
+    const pass = Boolean(matchingIcon);
+
+    let message;
+    if (pass) {
+      message = `${element.outerHTML} contains the sprite icon "${iconName}"!`;
+    } else {
+      message = `${element.outerHTML} does not contain the sprite icon "${iconName}"!`;
+
+      const existingIcons = iconReferences.map(reference => {
+        const iconUrl = reference.getAttribute('xlink:href');
+        return `"${iconUrl.replace(/^.+#/, '')}"`;
+      });
+      if (existingIcons.length > 0) {
+        message += ` (only found ${existingIcons.join(',')})`;
+      }
+    }
+
+    return {
+      pass,
+      message: () => message,
+    };
+  },
+};