diff --git a/bin/media/audio_core/test/audio_renderer_sync_test.cc b/bin/media/audio_core/test/audio_renderer_sync_test.cc
index 20887f5..47f3982 100644
--- a/bin/media/audio_core/test/audio_renderer_sync_test.cc
+++ b/bin/media/audio_core/test/audio_renderer_sync_test.cc
@@ -41,13 +41,6 @@
 };
 
 //
-// AudioRendererSyncTest_Negative
-//
-// Separate test class, purely for test case categorization, for cases in which
-// we expect the binding to disconnect -- and the AudioRendererSyncPtr to reset.
-class AudioRendererSyncTest_Negative : public AudioRendererSyncTest {};
-
-//
 // AudioRendererSync validation
 //
 // Basic validation of GetMinLeadTime() for the synchronous AudioRenderer.
@@ -58,6 +51,8 @@
   ASSERT_EQ(ZX_OK, audio_renderer_sync_->GetMinLeadTime(&min_lead_time))
       << kConnectionErr;
   EXPECT_GE(min_lead_time, 0) << "No MinLeadTime update received";
+
+  // TODO(mpuryear): test GetMinLeadTime with nullptr
 }
 
 // Before renderers are operational, multiple SetPcmStreamTypes should succeed.
@@ -87,12 +82,9 @@
   EXPECT_GE(min_lead_time, 0);
 }
 
-//
-// AudioRendererSync negative validation
-//
 // Before setting format, PlayNoReply should cause a Disconnect.
 // GetMinLeadTime is our way of verifying whether the connection survived.
-TEST_F(AudioRendererSyncTest_Negative, PlayNoReplyNoFormatCausesDisconnect) {
+TEST_F(AudioRendererSyncTest, PlayNoReplyNoFormatCausesDisconnect) {
   int64_t min_lead_time = -1;
   // First, make sure we still have a renderer at all.
   ASSERT_EQ(ZX_OK, audio_renderer_sync_->GetMinLeadTime(&min_lead_time));
@@ -109,7 +101,7 @@
 
 // Before setting format, PauseNoReply should cause a Disconnect.
 // GetMinLeadTime is our way of verifying whether the connection survived.
-TEST_F(AudioRendererSyncTest_Negative, PauseNoReplyWithoutFormat) {
+TEST_F(AudioRendererSyncTest, PauseNoReplyWithoutFormatCausesDisconnect) {
   int64_t min_lead_time = -1;
   // First, make sure we still have a renderer at all.
   ASSERT_EQ(ZX_OK, audio_renderer_sync_->GetMinLeadTime(&min_lead_time));
diff --git a/bin/media/audio_core/test/audio_renderer_test.cc b/bin/media/audio_core/test/audio_renderer_test.cc
index c033253..9fd653d 100644
--- a/bin/media/audio_core/test/audio_renderer_test.cc
+++ b/bin/media/audio_core/test/audio_renderer_test.cc
@@ -19,6 +19,8 @@
  protected:
   void SetUp() override;
   void TearDown() override;
+  void SetNegativeExpectations();
+  void ExpectDisconnect();
 
   std::shared_ptr<component::Services> environment_services_;
   fuchsia::media::AudioPtr audio_;
@@ -31,17 +33,6 @@
 };
 
 //
-// AudioRendererTestNegative
-//
-// A specialization of AudioRendererTest to validate scenarios where we expect
-// AudioRenderer bindings to disconnect (Audio bindings should be OK).
-class AudioRendererTest_Negative : public AudioRendererTest {
- protected:
-  void SetUp() override;
-  void ExpectDisconnect();
-};
-
-//
 // AudioRendererTest implementation
 //
 void AudioRendererTest::SetUp() {
@@ -57,6 +48,11 @@
   audio_renderer_.set_error_handler(err_handler);
 }
 
+void AudioRendererTest::SetNegativeExpectations() {
+  expect_error_ = true;
+  expect_renderer_ = false;
+}
+
 void AudioRendererTest::TearDown() {
   ASSERT_TRUE(audio_.is_bound());
   EXPECT_EQ(expect_error_, error_occurred_);
@@ -65,30 +61,46 @@
   ::gtest::RealLoopFixture::TearDown();
 }
 
-//
-// AudioRendererTest_Negative implementation
-//
-void AudioRendererTest_Negative::SetUp() {
-  AudioRendererTest::SetUp();
-
-  expect_error_ = true;
-  expect_renderer_ = false;
-}
-
-void AudioRendererTest_Negative::ExpectDisconnect() {
+void AudioRendererTest::ExpectDisconnect() {
   EXPECT_TRUE(RunLoopWithTimeoutOrUntil([this]() { return error_occurred_; },
                                         kDurationResponseExpected,
                                         kDurationGranularity));
 }
 
 //
+// AudioRenderer implements the base classes StreamBufferSet and StreamSink.
+
+//
+// StreamBufferSet validation
+//
+// TODO(mpuryear): test AddPayloadBuffer(uint32 id, handle<vmo> payload_buffer);
+// Also negative testing: bad id, null or bad handle
+
+// TODO(mpuryear): test RemovePayloadBuffer(uint32 id);
+// Also negative testing: unknown or already-removed id
+
+//
+// StreamSink validation
+//
+
+// TODO(mpuryear): test SendPacket(StreamPacket packet) -> ();
+// Also negative testing: malformed packet
+
+// TODO(mpuryear): test SendPacketNoReply(StreamPacket packet);
+// Also negative testing: malformed packet
+
+// TODO(mpuryear): test EndOfStream();
+// Also proper sequence of callbacks/completions
+
+// TODO(mpuryear): test DiscardAllPackets() -> ();
+// Also when no packets, when started
+
+// TODO(mpuryear): test DiscardAllPacketsNoReply();
+// Also when no packets, when started
+
+//
 // AudioRenderer validation
 //
-//
-// TODO(mpuryear): Remaining test coverage work within AudioRenderer:
-// SetPtsUnits, SetPtsContinuityThreshold, SetReferenceClock;
-// Also, positive coverage for Play, PlayNoReply, Pause, PauseNoReply,
-//
 
 // AudioRenderer contains an internal state machine. To enter the "configured"
 // state, it must receive and successfully execute both SetPcmStreamType and
@@ -96,10 +108,6 @@
 // "operational" mode when any packets are enqueued (received and not yet played
 // and/or released).
 
-// TODO(mpuryear): add tests to validate the following --
-// **** Basic API validation for asynchronous AudioRenderer:
-// SetPayloadBuffer, SendPacket, SendPacketNoReply, Flush.
-
 // **** Before we enter Configured mode:
 // SendPacket before SetPcmStreamType must fail.
 // SendPacket before SetPayloadBuffer must fail.
@@ -143,22 +151,29 @@
 }
 
 // TODO(mpuryear): test SetPtsUnits(uint32 tick_per_sec_num,uint32 denom);
+// Also negative testing: zero values, nullptrs, huge num/small denom
 
 // TODO(mpuryear): test SetPtsContinuityThreshold(float32 threshold_sec);
+// Also negative testing: NaN, negative, very large, infinity
 
 // TODO(mpuryear): test SetReferenceClock(handle reference_clock);
+// Also negative testing: null handle, bad handle, handle to something else
 
 // TODO(mpuryear): test Play(int64 ref_time, int64 med)->(int64 ref, int64 med);
 // Verify success after setting format and submitting buffers.
+// Also: when already in Play, very positive vals, very negative vals
 
 // TODO(mpuryear): test PlayNoReply(int64 reference_time, int64 media_time);
 // Verify success after setting format and submitting buffers.
+// Also: when already in Play, very positive vals, very negative vals
 
 // TODO(mpuryear): test Pause()->(int64 reference_time, int64 media_time);
 // Verify success after setting format and submitting buffers.
+// Also: when already in Pause
 
 // TODO(mpuryear): test PauseNoReply();
 // Verify success after setting format and submitting buffers.
+// Also: when already in Pause
 
 // Validate MinLeadTime events, when enabled.
 TEST_F(AudioRendererTest, EnableMinLeadTimeEvents) {
@@ -284,13 +299,11 @@
 }
 
 //
-// AudioRendererTest_Negative
-//
-// Separate test class for cases in which we expect the AudioRenderer binding to
+// SetStreamType is not yet implemented. We expect the AudioRenderer binding to
 // disconnect, and our AudioRenderer interface ptr to be reset.
-//
-// SetStreamType is not yet implemented and expected to cause a Disconnect.
-TEST_F(AudioRendererTest_Negative, SetStreamType) {
+TEST_F(AudioRendererTest, SetStreamType) {
+  SetNegativeExpectations();
+
   fuchsia::media::AudioStreamType stream_format;
   stream_format.sample_format = fuchsia::media::AudioSampleFormat::SIGNED_16;
   stream_format.channels = 1;
@@ -306,13 +319,10 @@
   ExpectDisconnect();
 }
 
-// TODO(mpuryear): negative tests for the following:
-//    SetPtsUnits(uint32 tick_per_sec_num,uint32 denom)
-//    SetPtsContinuityThreshold(float32 threshold_sec)
-//    SetReferenceClock(handle reference_clock)
-
 // Before setting format, Play should not succeed.
-TEST_F(AudioRendererTest_Negative, PlayWithoutFormat) {
+TEST_F(AudioRendererTest, PlayWithoutFormat) {
+  SetNegativeExpectations();
+
   int64_t ref_time_received = -1;
   int64_t media_time_received = -1;
 
@@ -331,7 +341,9 @@
 }
 
 // After setting format but before submitting buffers, Play should not succeed.
-TEST_F(AudioRendererTest_Negative, PlayWithoutBuffers) {
+TEST_F(AudioRendererTest, PlayWithoutBuffers) {
+  SetNegativeExpectations();
+
   fuchsia::media::AudioStreamType format;
   format.sample_format = fuchsia::media::AudioSampleFormat::FLOAT;
   format.channels = 1;
@@ -356,7 +368,9 @@
 }
 
 // Before setting format, PlayNoReply should cause a Disconnect.
-TEST_F(AudioRendererTest_Negative, PlayNoReplyWithoutFormat) {
+TEST_F(AudioRendererTest, PlayNoReplyWithoutFormat) {
+  SetNegativeExpectations();
+
   audio_renderer_->PlayNoReply(fuchsia::media::NO_TIMESTAMP,
                                fuchsia::media::NO_TIMESTAMP);
 
@@ -365,7 +379,9 @@
 }
 
 // Before setting format, Pause should not succeed.
-TEST_F(AudioRendererTest_Negative, PauseWithoutFormat) {
+TEST_F(AudioRendererTest, PauseWithoutFormat) {
+  SetNegativeExpectations();
+
   int64_t ref_time_received = -1;
   int64_t media_time_received = -1;
 
@@ -382,7 +398,9 @@
 }
 
 // After setting format but before submitting buffers, Pause should not succeed.
-TEST_F(AudioRendererTest_Negative, PauseWithoutBuffers) {
+TEST_F(AudioRendererTest, PauseWithoutBuffers) {
+  SetNegativeExpectations();
+
   fuchsia::media::AudioStreamType format;
   format.sample_format = fuchsia::media::AudioSampleFormat::FLOAT;
   format.channels = 1;
@@ -405,7 +423,9 @@
 }
 
 // Before setting format, PauseNoReply should cause a Disconnect.
-TEST_F(AudioRendererTest_Negative, PauseNoReplyWithoutFormat) {
+TEST_F(AudioRendererTest, PauseNoReplyWithoutFormat) {
+  SetNegativeExpectations();
+
   audio_renderer_->PauseNoReply();
 
   // Disconnect callback should be received.
diff --git a/bin/media/audio_core/test/audio_sync_test.cc b/bin/media/audio_core/test/audio_sync_test.cc
index e99c74a..d32c5c0 100644
--- a/bin/media/audio_core/test/audio_sync_test.cc
+++ b/bin/media/audio_core/test/audio_sync_test.cc
@@ -37,11 +37,6 @@
 };
 
 //
-// TODO(mpuryear): AudioSyncTest_Negative class and tests, for cases where
-// we expect AudioSync binding to disconnect, and AudioSyncPtr to be reset.
-//
-
-//
 // AudioCoreSync validation
 // Tests of the synchronously-proxied Audio interface: AudioSync.
 //
diff --git a/bin/media/audio_core/test/audio_test.cc b/bin/media/audio_core/test/audio_test.cc
index 07a47a6..c144c03 100644
--- a/bin/media/audio_core/test/audio_test.cc
+++ b/bin/media/audio_core/test/audio_test.cc
@@ -197,11 +197,6 @@
 }
 
 //
-// TODO(mpuryear): AudioTest_Negative class and tests, for cases where we
-// expect Audio binding to disconnect -- and Audio interface ptr to be reset.
-//
-
-//
 // Audio validation
 // Tests of the asynchronous Audio interface.
 //
@@ -318,6 +313,10 @@
   EXPECT_TRUE(audio_.is_bound());
 }
 
+// TODO(mpuryear): Test cases where we expect Audio binding to disconnect.
+// Possibilities: null/malformed request (CreateAudioRenderer / Capturer),
+// out-of-range enum (SetOutputRoutingPolicy), NAN float (SetSystemGain).
+
 //
 // Validation of System Gain and Mute
 //
diff --git a/bin/media/audio_core/test/gain_control_test.cc b/bin/media/audio_core/test/gain_control_test.cc
index cd67c5a..0936a38 100644
--- a/bin/media/audio_core/test/gain_control_test.cc
+++ b/bin/media/audio_core/test/gain_control_test.cc
@@ -148,6 +148,13 @@
   SetUpGainControl2();
 }
 
+// For tests that cause a GainControl to disconnect, set these expectations.
+void GainControlTestBase::SetNegativeExpectations() {
+  expect_null_api_ = true;
+  expect_error_ = true;
+  expect_null_gain_control_ = true;
+}
+
 // Set Gain, asserting that state is already reset so error can be detected.
 void GainControlTestBase::SetGain(float gain_db) {
   // On initialization and every Receive...Callback(), this is set to false.
@@ -287,10 +294,12 @@
   EXPECT_TRUE(ReceiveNoGainCallback());
 }
 
-// For RenderGainControlTest_Negative/CaptureGainControlTest_Negative.
+// For negative expectations.
 //
 // Setting gain too high should cause a disconnect.
 void GainControlTestBase::TestSetGainTooHigh() {
+  SetNegativeExpectations();
+
   constexpr float expect_gain_db = kTooHighGainDb;
   SetGain(expect_gain_db);
 
@@ -300,6 +309,8 @@
 
 // Setting gain too low should cause a disconnect.
 void GainControlTestBase::TestSetGainTooLow() {
+  SetNegativeExpectations();
+
   constexpr float expect_gain_db = kTooLowGainDb;
   SetGain(expect_gain_db);
 
@@ -323,7 +334,9 @@
 // Single renderer with one gain control: Gain, Mute and GainMute combo.
 //
 TEST_F(RenderGainControlTest, SetGain) { TestSetGain(); }
+
 TEST_F(RenderGainControlTest, SetMute) { TestSetMute(); }
+
 TEST_F(RenderGainControlTest, SetGainMute) { TestSetGainMute(); }
 
 // TODO(mpuryear): Ramp-related tests (render). Relevant FIDL signature is:
@@ -331,9 +344,17 @@
 
 // TODO(mpuryear): Validate GainChange notifications of gainramps.
 
-TEST_F(RenderGainControlTest, DuplicateSetGain) { TestDuplicateSetGain(); }
+// N.B. DuplicateSetGain behavior is tested in RendererTwoGainControlsTest.
 TEST_F(RenderGainControlTest, DuplicateSetMute) { TestDuplicateSetMute(); }
 
+TEST_F(RenderGainControlTest, SetGainTooHigh) { TestSetGainTooHigh(); }
+
+TEST_F(RenderGainControlTest, SetGainTooLow) { TestSetGainTooLow(); }
+
+// TODO(mpuryear): SetGain(NAN) - should have no effect
+
+// TODO(mpuryear): Ramp-related negative tests, across all scenarios
+
 // CaptureGainControlTest
 //
 void CaptureGainControlTest::SetUp() {
@@ -346,48 +367,33 @@
 // Single capturer with one gain control
 //
 TEST_F(CaptureGainControlTest, SetGain) { TestSetGain(); }
+
 TEST_F(CaptureGainControlTest, SetMute) { TestSetMute(); }
+
 TEST_F(CaptureGainControlTest, SetGainMute) { TestSetGainMute(); }
 
 // TODO(mpuryear): Ramp-related tests (capture)
 
 TEST_F(CaptureGainControlTest, DuplicateSetGain) { TestDuplicateSetGain(); }
-TEST_F(CaptureGainControlTest, DuplicateSetMute) { TestDuplicateSetMute(); }
+// N.B. DuplicateSetMute behavior is tested in CapturerTwoGainControlsTest.
 
-// RenderGainControlTest_Negative
-// Specialization when we expect GainControl/AudioRenderer to disconnect.
-//
-void RenderGainControlTest_Negative::SetUp() {
-  RenderGainControlTest::SetUp();
+TEST_F(CaptureGainControlTest, SetGainTooHigh) { TestSetGainTooHigh(); }
 
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
+TEST_F(CaptureGainControlTest, SetGainTooLow) { TestSetGainTooLow(); }
 
-TEST_F(RenderGainControlTest_Negative, SetGainTooHigh) { TestSetGainTooHigh(); }
-TEST_F(RenderGainControlTest_Negative, SetGainTooLow) { TestSetGainTooLow(); }
-// TODO(mpuryear): Ramp-related negative tests, across all scenarios
-
-// CaptureGainControlTest_Negative
-// Specialization when we expect GainControl/AudioCapturer to disconnect.
-//
-void CaptureGainControlTest_Negative::SetUp() {
-  CaptureGainControlTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
-
-TEST_F(CaptureGainControlTest_Negative, SetGainTooHigh) {
-  TestSetGainTooHigh();
-}
-TEST_F(CaptureGainControlTest_Negative, SetGainTooLow) { TestSetGainTooLow(); }
+// TODO(mpuryear): SetGain(NAN) - should have no effect
 
 // SiblingGainControlsTest
 // On a renderer/capturer, sibling GainControls receive identical notifications.
 //
+// For tests that cause a GainControl to disconnect, set these expectations.
+void SiblingGainControlsTest::SetNegativeExpectations() {
+  GainControlTestBase::SetNegativeExpectations();
+
+  expect_null_gain_control_2_ = true;
+  expect_error_2_ = true;
+}
+
 // Tests expect a gain callback on both gain_controls, with the provided gain_db
 // and mute values -- and no errors.
 bool SiblingGainControlsTest::ReceiveGainCallback(float gain_db, bool mute) {
@@ -492,15 +498,20 @@
 TEST_F(RendererTwoGainControlsTest, BothControlsReceiveGainNotifications) {
   TestSetGain();
 }
+
 TEST_F(RendererTwoGainControlsTest, BothControlsReceiveMuteNotifications) {
   TestSetMute();
 }
+
 TEST_F(RendererTwoGainControlsTest, DuplicateSetGain) {
   TestDuplicateSetGain();
 }
-TEST_F(RendererTwoGainControlsTest, DuplicateSetMute) {
-  TestDuplicateSetMute();
-}
+
+// N.B. DuplicateSetMute behavior is tested in RendererGainControlTest.
+
+TEST_F(RendererTwoGainControlsTest, SetGainTooHigh) { TestSetGainTooHigh(); }
+
+TEST_F(RendererTwoGainControlsTest, SetGainTooLow) { TestSetGainTooLow(); }
 
 // CapturerTwoGainControlsTest
 // Capturer with two gain controls: both should receive identical notifications.
@@ -516,55 +527,19 @@
 TEST_F(CapturerTwoGainControlsTest, BothControlsReceiveGainNotifications) {
   TestSetGain();
 }
+
 TEST_F(CapturerTwoGainControlsTest, BothControlsReceiveMuteNotifications) {
   TestSetMute();
 }
-TEST_F(CapturerTwoGainControlsTest, DuplicateSetGain) {
-  TestDuplicateSetGain();
-}
+
+// N.B. DuplicateSetGain behavior is tested in CapturerGainControlTest.
 TEST_F(CapturerTwoGainControlsTest, DuplicateSetMute) {
   TestDuplicateSetMute();
 }
 
-// RendererTwoGainControlsTest_Negative
-// Specialization when we expect GainControls and Renderer to disconnect.
-//
-void RendererTwoGainControlsTest_Negative::SetUp() {
-  RendererTwoGainControlsTest::SetUp();
+TEST_F(CapturerTwoGainControlsTest, SetGainTooHigh) { TestSetGainTooHigh(); }
 
-  expect_null_api_ = true;
-  expect_null_gain_control_ = true;
-  expect_null_gain_control_2_ = true;
-  expect_error_ = true;
-  expect_error_2_ = true;
-}
-
-TEST_F(RendererTwoGainControlsTest_Negative, SetGainTooHigh) {
-  TestSetGainTooHigh();
-}
-TEST_F(RendererTwoGainControlsTest_Negative, SetGainTooLow) {
-  TestSetGainTooLow();
-}
-
-// CapturerTwoGainControlsTest_Negative
-// Specialization when we expect GainControls and Capturer to disconnect.
-//
-void CapturerTwoGainControlsTest_Negative::SetUp() {
-  CapturerTwoGainControlsTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_null_gain_control_ = true;
-  expect_null_gain_control_2_ = true;
-  expect_error_ = true;
-  expect_error_2_ = true;
-}
-
-TEST_F(CapturerTwoGainControlsTest_Negative, SetGainTooHigh) {
-  TestSetGainTooHigh();
-}
-TEST_F(CapturerTwoGainControlsTest_Negative, SetGainTooLow) {
-  TestSetGainTooLow();
-}
+TEST_F(CapturerTwoGainControlsTest, SetGainTooLow) { TestSetGainTooLow(); }
 
 // IndependentGainControlsTest
 // Verify that GainControls on different API instances are fully independent.
@@ -681,6 +656,9 @@
   TestSetMute();
 }
 
+// We expect primary GainControl/Renderer to disconnect.
+TEST_F(TwoRenderersGainControlsTest, SetGainTooLow) { TestSetGainTooLow(); }
+
 // RendererCapturerGainControlsTest
 // Renderer gain control should not affect capturer gain control.
 //
@@ -699,6 +677,11 @@
   TestSetGain();
 }
 
+// We expect primary GainControl/Renderer to disconnect.
+TEST_F(RendererCapturerGainControlsTest, SetGainTooHigh) {
+  TestSetGainTooHigh();
+}
+
 // CapturerRendererGainControlsTest
 // Capturer gain control should not affect renderer gain control.
 //
@@ -717,6 +700,11 @@
   TestSetGain();
 }
 
+// We expect primary GainControl/Capturer to disconnect.
+TEST_F(CapturerRendererGainControlsTest, SetGainTooHigh) {
+  TestSetGainTooHigh();
+}
+
 // TwoCapturersGainControlsTest
 // Two capturers, each with a gain control: we expect no cross-impact.
 //
@@ -734,64 +722,7 @@
   TestSetMute();
 }
 
-// TwoRenderersGainControlsTest_Negative
-// Specialization when we expect one GainControl/Renderer to disconnect.
-//
-void TwoRenderersGainControlsTest_Negative::SetUp() {
-  TwoRenderersGainControlsTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
-
-TEST_F(TwoRenderersGainControlsTest_Negative, SetGainTooLow) {
-  TestSetGainTooLow();
-}
-
-// RendererCapturerGainControlsTest_Negative
-// Specialization when we expect one GainControl/Renderer to disconnect.
-//
-void RendererCapturerGainControlsTest_Negative::SetUp() {
-  RendererCapturerGainControlsTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
-
-TEST_F(RendererCapturerGainControlsTest_Negative, SetGainTooHigh) {
-  TestSetGainTooHigh();
-}
-
-// CapturerRendererGainControlsTest_Negative
-// Specialization when we expect one GainControl/Capturer to disconnect.
-//
-void CapturerRendererGainControlsTest_Negative::SetUp() {
-  CapturerRendererGainControlsTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
-
-TEST_F(CapturerRendererGainControlsTest_Negative, SetGainTooHigh) {
-  TestSetGainTooHigh();
-}
-
-// TwoCapturersGainControlsTest_Negative
-// Specialization when we expect one GainControl/Capturer to disconnect.
-//
-void TwoCapturersGainControlsTest_Negative::SetUp() {
-  TwoCapturersGainControlsTest::SetUp();
-
-  expect_null_api_ = true;
-  expect_error_ = true;
-  expect_null_gain_control_ = true;
-}
-
-TEST_F(TwoCapturersGainControlsTest_Negative, SetGainTooLow) {
-  TestSetGainTooLow();
-}
+// We expect primary GainControl/Capturer to disconnect.
+TEST_F(TwoCapturersGainControlsTest, SetGainTooLow) { TestSetGainTooLow(); }
 
 }  // namespace media::audio::test
diff --git a/bin/media/audio_core/test/gain_control_test.h b/bin/media/audio_core/test/gain_control_test.h
index 1f7156b..1016cf4 100644
--- a/bin/media/audio_core/test/gain_control_test.h
+++ b/bin/media/audio_core/test/gain_control_test.h
@@ -40,6 +40,7 @@
   void SetUpGainControl2OnCapturer();
   void SetUpGainControl2OnRenderer2();
   void SetUpGainControl2OnCapturer2();
+  virtual void SetNegativeExpectations();
 
   void SetGain(float gain_db);
   void SetMute(bool mute);
@@ -110,27 +111,13 @@
   bool ApiIsNull() final { return !audio_capturer_.is_bound(); }
 };
 
-// RenderGainControlTest_Negative
-//
-// Specialization when we expect GainControl/AudioRenderer to disconnect.
-class RenderGainControlTest_Negative : public RenderGainControlTest {
- protected:
-  void SetUp() final;
-};
-
-// CaptureGainControlTest_Negative
-//
-// Specialization when we expect GainControl/AudioCapturer to disconnect.
-class CaptureGainControlTest_Negative : public CaptureGainControlTest {
- protected:
-  void SetUp() final;
-};
-
 // SiblingGainControlsTest
 //
 // On a renderer/capturer, sibling GainControls receive identical notifications.
 class SiblingGainControlsTest : public GainControlTestBase {
  protected:
+  void SetNegativeExpectations() override;
+
   // Absorb a gain callback from the sibling GainControl as well.
   bool ReceiveGainCallback(float gain_db, bool mute) final;
   bool ReceiveNoGainCallback() final;
@@ -157,24 +144,6 @@
   bool ApiIsNull() final { return !audio_capturer_.is_bound(); }
 };
 
-// RendererTwoGainControlsTest_Negative
-//
-// Specialization when we expect GainControls and Renderer to disconnect.
-class RendererTwoGainControlsTest_Negative
-    : public RendererTwoGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
-// CapturerTwoGainControlsTest_Negative
-//
-// Specialization when we expect GainControls and Capturer to disconnect.
-class CapturerTwoGainControlsTest_Negative
-    : public CapturerTwoGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
 // IndependentGainControlsTest
 //
 // Verify that GainControls on different API instances are fully independent.
@@ -233,42 +202,6 @@
   }
 };
 
-// TwoRenderersGainControlsTest_Negative
-//
-// Specialization when we expect one GainControl/Renderer to disconnect.
-class TwoRenderersGainControlsTest_Negative
-    : public TwoRenderersGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
-// RendererCapturerGainControlsTest_Negative
-//
-// Specialization when we expect one GainControl/Renderer to disconnect.
-class RendererCapturerGainControlsTest_Negative
-    : public RendererCapturerGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
-// CapturerRendererGainControlsTest_Negative
-//
-// Specialization when we expect one GainControl/Capturer to disconnect.
-class CapturerRendererGainControlsTest_Negative
-    : public CapturerRendererGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
-// TwoCapturersGainControlsTest_Negative
-//
-// Specialization when we expect one GainControl/Capturer to disconnect.
-class TwoCapturersGainControlsTest_Negative
-    : public TwoCapturersGainControlsTest {
- protected:
-  void SetUp() final;
-};
-
 }  // namespace test
 }  // namespace audio
 }  // namespace media