[v6] Implement Realtime Database (#2195)

* [database] recreate database branch based off of #2185

* [database] cleanup linting issues

* [database] enable tests

* [database] add to tests deps

packages/database/e2e/internal/connected.e2e.js

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2016-present Invertase Limited & Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this library 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.
+ *
+ */
+
+describe(`database().ref('.info/connected')`, () => {
+  after(() => firebase.database().goOnline());
+
+  it('returns false when used with once', async () => {
+    const snapshot = await firebase
+      .database()
+      .ref('.info/connected')
+      .once('value');
+    snapshot.val().should.equal(false);
+  });
+
+  it('returns true when used with once with a previous call', async () => {
+    await firebase
+      .database()
+      .ref('tests')
+      .once('value');
+    const snapshot = await firebase
+      .database()
+      .ref('.info/connected')
+      .once('value');
+    snapshot.val().should.equal(true);
+  });
+
+  it('subscribes to online state', async () => {
+    const callback = sinon.spy();
+    await firebase.database().goOffline();
+
+    const ref = firebase.database().ref('.info/connected');
+
+    const handler = $ => {
+      callback($.val());
+    };
+
+    ref.on('value', handler);
+
+    await Utils.sleep(1000);
+    await firebase.database().goOnline();
+    await Utils.sleep(1000);
+    ref.off('value', handler);
+
+    callback.should.be.calledTwice();
+    callback.getCall(0).args[0].should.equal(false);
+    callback.getCall(1).args[0].should.equal(true);
+  });
+});

packages/database/e2e/internal/serverTimeOffset.e2e.js

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2016-present Invertase Limited & Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this library 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.
+ *
+ */
+
+describe(`database().ref('.info/serverTimeOffset')`, () => {
+  it('returns a valid number value', async () => {
+    const snapshot = await firebase
+      .database()
+      .ref('.info/serverTimeOffset')
+      .once('value');
+
+    should.equal(typeof snapshot.val(), 'number');
+  });
+});