fix(tests): add missing HistoryLabels tests

ui/src/Components/Labels/HistoryLabel/index.test.js

@@ -0,0 +1,34 @@
+import React from "react";
+
+import { shallow } from "enzyme";
+
+import { AlertStore } from "Stores/AlertStore";
+
+import { HistoryLabel } from ".";
+
+let alertStore;
+
+beforeEach(() => {
+  alertStore = new AlertStore([]);
+});
+
+describe("<HistoryLabel />", () => {
+  it("renders name, matcher and value if all are set", () => {
+    const tree = shallow(
+      <HistoryLabel
+        alertStore={alertStore}
+        name="foo"
+        matcher="="
+        value="bar"
+      />
+    );
+    expect(tree.text()).toBe("foo=bar");
+  });
+
+  it("renders only value if name is falsey", () => {
+    const tree = shallow(
+      <HistoryLabel alertStore={alertStore} name="" matcher="" value="bar" />
+    );
+    expect(tree.text()).toBe("bar");
+  });
+});