[test] Put front_end/models/ unit tests next to the source code.

DISABLE_THIRD_PARTY_CHECK=Moving unit tests.

Bug: b:325903709, b:323795674
Change-Id: Ied7584d269787294dd7cbc80faeaf33eed49ca67
Doc: http://go/chrome-devtools:move-unit-tests-design
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/5308063
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Auto-Submit: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>

front_end/models/javascript_metadata/JavaScriptMetadata.test.ts

@@ -0,0 +1,62 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import * as JavascriptMetadata from './javascript_metadata.js';
+
+describe('JavaScriptMetadata', () => {
+  let metadata: JavascriptMetadata.JavaScriptMetadata.JavaScriptMetadataImpl;
+
+  before(() => {
+    metadata = new JavascriptMetadata.JavaScriptMetadata.JavaScriptMetadataImpl();
+  });
+
+  it('retrieves native signature by name', () => {
+    const signatures = metadata.signaturesForNativeFunction('webkitRequestFullScreen');
+    assert.deepEqual(signatures, [['?options']]);
+  });
+
+  it('does not retrieve native signatures that are bound to an instance', () => {
+    const signatures = metadata.signaturesForNativeFunction('find');
+    assert.deepEqual(signatures, null);
+  });
+
+  describe('with static methods', () => {
+    it('retrieves by name and class', () => {
+      const signatures = metadata.signaturesForStaticMethod('from', 'Array');
+      assert.deepEqual(signatures, [['iterable', '?mapfn', '?thisArg'], ['arrayLike', '?mapfn', '?thisArg']]);
+    });
+
+    it('does not retrieve methods that are bound to an instance', () => {
+      const signatures = metadata.signaturesForStaticMethod('includes', 'Array');
+      assert.deepEqual(signatures, null);
+    });
+
+    it('handles a non-existing class', () => {
+      const signatures = metadata.signaturesForStaticMethod('includes', 'bogus');
+      assert.deepEqual(signatures, null);
+    });
+  });
+
+  describe('with instance methods', () => {
+    it('retrieves by name and class', () => {
+      const signatures = metadata.signaturesForInstanceMethod('assign', 'HTMLSlotElement');
+      assert.deepEqual(signatures, [['...nodes']]);
+    });
+
+    it('does not retrieve methods that are unbound', () => {
+      const signatures = metadata.signaturesForInstanceMethod('webkitRequestFullScreen', 'window');
+      assert.deepEqual(signatures, null);
+    });
+
+    it('does not retrieve static methods', () => {
+      const signatures = metadata.signaturesForInstanceMethod('from', 'Array');
+      assert.deepEqual(signatures, null);
+    });
+
+    it('handles a non-existing class', () => {
+      const signatures = metadata.signaturesForInstanceMethod('from', 'Sheep');
+      assert.deepEqual(signatures, null);
+    });
+  });
+});