drm_hwcomposer: Add PipelineBindable unit tests

Change-Id: Iada6f16cb3b72f38cbaad1b71b38c8ef201c4722

drm/DrmDisplayPipeline.cpp

@@ -29,25 +29,6 @@
 
 namespace android::drm_hwcomposer {
 
-template <class O>
-auto PipelineBindable<O>::BindPipeline(const DrmDisplayPipeline *pipeline,
-                                       bool return_object_if_bound)
-    -> std::shared_ptr<BindingOwner<O>> {
-  auto owner_object = owner_object_.lock();
-  if (owner_object) {
-    if (bound_pipeline_ == pipeline && return_object_if_bound) {
-      return owner_object;
-    }
-
-    return {};
-  }
-  owner_object = std::make_shared<BindingOwner<O>>(static_cast<O *>(this));
-
-  owner_object_ = owner_object;
-  bound_pipeline_ = pipeline;
-  return owner_object;
-}
-
 static auto TryCreatePipeline(DrmDevice &dev, DrmConnector &connector,
                               DrmEncoder &enc, DrmCrtc &crtc)
     -> std::unique_ptr<DrmDisplayPipeline> {

drm/DrmDisplayPipeline.h

@@ -42,9 +42,24 @@ class PipelineBindable {
     return bound_pipeline_;
   }
 
+  // Header implementation required for template instantiation.
   auto BindPipeline(const DrmDisplayPipeline *pipeline,
                     bool return_object_if_bound = false)
-      -> std::shared_ptr<BindingOwner<O>>;
+      -> std::shared_ptr<BindingOwner<O>> {
+    auto owner_object = owner_object_.lock();
+    if (owner_object) {
+      if (bound_pipeline_ == pipeline && return_object_if_bound) {
+        return owner_object;
+      }
+
+      return {};
+    }
+    owner_object = std::make_shared<BindingOwner<O>>(static_cast<O *>(this));
+
+    owner_object_ = owner_object;
+    bound_pipeline_ = pipeline;
+    return owner_object;
+  }
 
  private:
   const DrmDisplayPipeline *bound_pipeline_;

drm/DrmDisplayPipelineTest.cpp

@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2025 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.
+ */
+
+#include <memory>
+
+#include <gtest/gtest.h>
+
+#include "DrmDisplayPipeline.h"
+
+namespace android::drm_hwcomposer {
+
+class NoOpBindable : public PipelineBindable<NoOpBindable> {};
+
+class DrmDisplayPipelineTest : public ::testing::Test {};
+
+TEST_F(DrmDisplayPipelineTest, BindPipeline_Success) {
+  const auto pipeline = std::make_unique<DrmDisplayPipeline>();
+  NoOpBindable bindable;
+
+  const auto binding = bindable.BindPipeline(pipeline.get(),
+                                             /*return_object_if_bound=*/true);
+
+  ASSERT_NE(binding, nullptr);
+  EXPECT_EQ(binding->Get()->GetPipeline(), pipeline.get());
+  EXPECT_EQ(binding->Get(), &bindable);
+}
+
+TEST_F(DrmDisplayPipelineTest, BindPipeline_SamePipelineReturnsSameBinding) {
+  const auto pipeline = std::make_unique<DrmDisplayPipeline>();
+  NoOpBindable bindable;
+
+  const auto binding1 = bindable.BindPipeline(pipeline.get(),
+                                              /*return_object_if_bound=*/true);
+  ASSERT_NE(binding1, nullptr);
+  EXPECT_EQ(binding1->Get()->GetPipeline(), pipeline.get());
+  EXPECT_EQ(binding1->Get(), &bindable);
+  const auto binding2 = bindable.BindPipeline(pipeline.get(),
+                                              /*return_object_if_bound=*/true);
+  EXPECT_EQ(binding1, binding2);
+}
+
+TEST_F(DrmDisplayPipelineTest,
+       BindPipeline_DifferentPipelineReturnsNullBinding) {
+  const auto pipeline1 = std::make_unique<DrmDisplayPipeline>();
+  const auto pipeline2 = std::make_unique<DrmDisplayPipeline>();
+  NoOpBindable bindable;
+
+  const auto binding1 = bindable.BindPipeline(pipeline1.get(),
+                                              /*return_object_if_bound=*/true);
+  ASSERT_NE(binding1, nullptr);
+  EXPECT_EQ(binding1->Get()->GetPipeline(), pipeline1.get());
+  EXPECT_EQ(binding1->Get(), &bindable);
+  const auto binding2 = bindable.BindPipeline(pipeline2.get(),
+                                              /*return_object_if_bound=*/true);
+  EXPECT_EQ(binding2, nullptr);
+}
+
+TEST_F(DrmDisplayPipelineTest,
+       BindPipeline_ReleasedBindingDoesntPreventNewBinding) {
+  const auto pipeline1 = std::make_unique<DrmDisplayPipeline>();
+  const auto pipeline2 = std::make_unique<DrmDisplayPipeline>();
+  NoOpBindable bindable;
+
+  auto binding1 = bindable.BindPipeline(pipeline1.get(),
+                                        /*return_object_if_bound=*/true);
+  ASSERT_NE(binding1, nullptr);
+  EXPECT_EQ(binding1->Get()->GetPipeline(), pipeline1.get());
+  EXPECT_EQ(binding1->Get(), &bindable);
+  binding1.reset();
+  const auto binding2 = bindable.BindPipeline(pipeline2.get(),
+                                              /*return_object_if_bound=*/true);
+  ASSERT_NE(binding2, nullptr);
+  EXPECT_EQ(binding2->Get()->GetPipeline(), pipeline2.get());
+  EXPECT_EQ(binding2->Get(), &bindable);
+}
+
+}  // namespace android::drm_hwcomposer