r_submix: Add some tests

Add simple tests to verify remote submix behavior regarding
blocking writes. Currently one of the tests fails (does not finish),
this needs to be fixed.

Also fixed some minor issues in remote submix module code.

Bug: 73175392
Test: r_submix_tests
Change-Id: Ic88d0c385c0102e35b4f751f9c5cd8a6488949c8
diff --git a/modules/audio_remote_submix/tests/Android.bp b/modules/audio_remote_submix/tests/Android.bp
new file mode 100644
index 0000000..8e4d42d
--- /dev/null
+++ b/modules/audio_remote_submix/tests/Android.bp
@@ -0,0 +1,29 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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.
+
+cc_test {
+    name: "r_submix_tests",
+
+    srcs: ["remote_submix_tests.cpp"],
+
+    shared_libs: [
+        "libhardware",
+        "liblog",
+        "libutils",
+    ],
+
+    cflags: ["-Wall", "-Werror", "-O0", "-g",],
+
+    header_libs: ["libaudiohal_headers"],
+}