Add some unit tests for QueryMatcher

Which 1) has a fairly complex interface with lots of subtleties and
2) is really trivial to unit test.

test/autocomplete/QueryMatcher-test.js

@@ -0,0 +1,136 @@
+/*
+Copyright 2018 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import expect from 'expect';
+
+import QueryMatcher from '../../src/autocomplete/QueryMatcher';
+
+const OBJECTS = [
+    { name: "Mel B", nick: "Scary" },
+    { name: "Mel C", nick: "Sporty" },
+    { name: "Emma", nick: "Baby" },
+    { name: "Geri", nick: "Ginger" },
+    { name: "Victoria", nick: "Posh" },
+];
+
+describe('QueryMatcher', function() {
+    it('Returns results by key', function() {
+        const qm = new QueryMatcher(OBJECTS, {keys: ["name"]});
+        const results = qm.match('Geri');
+
+        expect(results.length).toBe(1);
+        expect(results[0].name).toBe('Geri');
+    });
+
+    it('Returns results by prefix', function() {
+        const qm = new QueryMatcher(OBJECTS, {keys: ["name"]});
+        const results = qm.match('Ge');
+
+        expect(results.length).toBe(1);
+        expect(results[0].name).toBe('Geri');
+    });
+
+    it('Matches case-insensitive', function() {
+        const qm = new QueryMatcher(OBJECTS, {keys: ["name"]});
+        const results = qm.match('geri');
+
+        expect(results.length).toBe(1);
+        expect(results[0].name).toBe('Geri');
+    });
+
+    it('Matches ignoring accents', function() {
+        const qm = new QueryMatcher([{name: "Gëri", foo: 46}], {keys: ["name"]});
+        const results = qm.match('geri');
+
+        expect(results.length).toBe(1);
+        expect(results[0].foo).toBe(46);
+    });
+
+    it('Returns multiple results in order of search string appearance', function() {
+        const qm = new QueryMatcher(OBJECTS, {keys: ["name", "nick"]});
+        const results = qm.match('or');
+
+        expect(results.length).toBe(2);
+        expect(results[0].name).toBe('Mel C');
+        expect(results[1].name).toBe('Victoria');
+
+
+        qm.setObjects(OBJECTS.slice().reverse());
+        const reverseResults = qm.match('or');
+
+        // should still be in the same order: search string position
+        // takes precedence over input order
+        expect(reverseResults.length).toBe(2);
+        expect(reverseResults[0].name).toBe('Mel C');
+        expect(reverseResults[1].name).toBe('Victoria');
+    });
+
+    it('Returns results with search string in same place in insertion order', function() {
+        const qm = new QueryMatcher(OBJECTS, {keys: ["name"]});
+        const results = qm.match('Mel');
+
+        expect(results.length).toBe(2);
+        expect(results[0].name).toBe('Mel B');
+        expect(results[1].name).toBe('Mel C');
+
+
+        qm.setObjects(OBJECTS.slice().reverse());
+
+        const reverseResults = qm.match('Mel');
+
+        expect(reverseResults.length).toBe(2);
+        expect(reverseResults[0].name).toBe('Mel C');
+        expect(reverseResults[1].name).toBe('Mel B');
+    });
+
+    it('Returns numeric results in correct order (input pos)', function() {
+        // regression test for depending on object iteration order
+        const qm = new QueryMatcher([
+            {name: "123456badger"},
+            {name: "123456"},
+        ], {keys: ["name"]});
+        const results = qm.match('123456');
+
+        expect(results.length).toBe(2);
+        expect(results[0].name).toBe('123456badger');
+        expect(results[1].name).toBe('123456');
+    });
+
+    it('Returns numeric results in correct order (query pos)', function() {
+        const qm = new QueryMatcher([
+            {name: "999999123456"},
+            {name: "123456badger"},
+        ], {keys: ["name"]});
+        const results = qm.match('123456');
+
+        expect(results.length).toBe(2);
+        expect(results[0].name).toBe('123456badger');
+        expect(results[1].name).toBe('999999123456');
+    });
+
+    it('Returns results by function', function() {
+        const qm = new QueryMatcher(OBJECTS, {
+            keys: ["name"],
+            funcs: [x => x.name.replace('Mel', 'Emma')],
+        });
+
+        const results = qm.match('Emma');
+        expect(results.length).toBe(3);
+        expect(results[0].name).toBe('Mel B');
+        expect(results[1].name).toBe('Mel C');
+        expect(results[2].name).toBe('Emma');
+    });
+});