diff --git a/services/surfaceflinger/CompositionEngine/Android.bp b/services/surfaceflinger/CompositionEngine/Android.bp
index 455e623..e316190 100644
--- a/services/surfaceflinger/CompositionEngine/Android.bp
+++ b/services/surfaceflinger/CompositionEngine/Android.bp
@@ -127,6 +127,10 @@
 cc_test {
     name: "libcompositionengine_test",
     test_suites: ["device-tests"],
+    include_dirs: [
+        "frameworks/native/services/surfaceflinger/common/include",
+        "frameworks/native/services/surfaceflinger/tests/unittests",
+    ],
     defaults: ["libcompositionengine_defaults"],
     srcs: [
         "tests/planner/CachedSetTest.cpp",
diff --git a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
index 748d87b..7be5fe3 100644
--- a/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/CompositionEngine.cpp
@@ -90,29 +90,37 @@
 }
 
 namespace {
-int numDisplaysWithOffloadPresentSupport(const CompositionRefreshArgs& args) {
-    if (!FlagManager::getInstance().multithreaded_present() || args.outputs.size() < 2) {
-        return 0;
+void offloadOutputs(Outputs& outputs) {
+    if (!FlagManager::getInstance().multithreaded_present() || outputs.size() < 2) {
+        return;
     }
 
-    int numEligibleDisplays = 0;
-    // Only run present in multiple threads if all HWC-enabled displays
-    // being refreshed support it.
-    if (!std::all_of(args.outputs.begin(), args.outputs.end(),
-                     [&numEligibleDisplays](const auto& output) {
-                         if (!ftl::Optional(output->getDisplayId())
-                                      .and_then(HalDisplayId::tryCast)) {
-                             // Not HWC-enabled, so it is always
-                             // client-composited.
-                             return true;
-                         }
-                         const bool support = output->supportsOffloadPresent();
-                         numEligibleDisplays += static_cast<int>(support);
-                         return support;
-                     })) {
-        return 0;
+    ui::PhysicalDisplayVector<compositionengine::Output*> outputsToOffload;
+    for (const auto& output : outputs) {
+        if (!ftl::Optional(output->getDisplayId()).and_then(HalDisplayId::tryCast)) {
+            // Not HWC-enabled, so it is always client-composited. No need to offload.
+            continue;
+        }
+
+        // Only run present in multiple threads if all HWC-enabled displays
+        // being refreshed support it.
+        if (!output->supportsOffloadPresent()) {
+            return;
+        }
+        outputsToOffload.push_back(output.get());
     }
-    return numEligibleDisplays;
+
+    if (outputsToOffload.size() < 2) {
+        return;
+    }
+
+    // Leave the last eligible display on the main thread, which will
+    // allow it to run concurrently without an extra thread hop.
+    outputsToOffload.pop_back();
+
+    for (compositionengine::Output* output : outputsToOffload) {
+        output->offloadPresentNextFrame();
+    }
 }
 } // namespace
 
@@ -136,20 +144,7 @@
     // Offloading the HWC call for `present` allows us to simultaneously call it
     // on multiple displays. This is desirable because these calls block and can
     // be slow.
-    if (const int numEligibleDisplays = numDisplaysWithOffloadPresentSupport(args);
-        numEligibleDisplays > 1) {
-        // Leave the last eligible display on the main thread, which will
-        // allow it to run concurrently without an extra thread hop.
-        int numToOffload = numEligibleDisplays - 1;
-        for (auto& output : args.outputs) {
-            if (output->supportsOffloadPresent()) {
-                output->offloadPresentNextFrame();
-                if (--numToOffload == 0) {
-                    break;
-                }
-            }
-        }
-    }
+    offloadOutputs(args.outputs);
 
     ui::DisplayVector<ftl::Future<std::monostate>> presentFutures;
     for (const auto& output : args.outputs) {
diff --git a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
index a451ab2..602dd23 100644
--- a/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/CompositionEngineTest.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#include <com_android_graphics_surfaceflinger_flags.h>
+#include <common/test/FlagUtils.h>
 #include <compositionengine/CompositionRefreshArgs.h>
 #include <compositionengine/LayerFECompositionState.h>
 #include <compositionengine/impl/CompositionEngine.h>
@@ -29,6 +31,8 @@
 
 #include <variant>
 
+using namespace com::android::graphics::surfaceflinger;
+
 namespace android::compositionengine {
 namespace {
 
@@ -110,11 +114,9 @@
     EXPECT_CALL(*mOutput2, prepare(Ref(mRefreshArgs), _));
     EXPECT_CALL(*mOutput3, prepare(Ref(mRefreshArgs), _));
 
-    if (FlagManager::getInstance().multithreaded_present()) {
-        EXPECT_CALL(*mOutput1, getDisplayId()).WillOnce(Return(std::nullopt));
-        EXPECT_CALL(*mOutput2, getDisplayId()).WillOnce(Return(std::nullopt));
-        EXPECT_CALL(*mOutput3, getDisplayId()).WillOnce(Return(std::nullopt));
-    }
+    // All of mOutput<i> are StrictMocks. If the flag is true, it will introduce
+    // calls to getDisplayId, which are not relevant to this test.
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, false);
 
     // The last step is to actually present each output.
     EXPECT_CALL(*mOutput1, present(Ref(mRefreshArgs)))
@@ -272,5 +274,164 @@
     EXPECT_TRUE(mEngine.needsAnotherUpdate());
 }
 
+struct CompositionEngineOffloadTest : public testing::Test {
+    impl::CompositionEngine mEngine;
+    CompositionRefreshArgs mRefreshArgs;
+
+    std::shared_ptr<mock::Output> mDisplay1{std::make_shared<StrictMock<mock::Output>>()};
+    std::shared_ptr<mock::Output> mDisplay2{std::make_shared<StrictMock<mock::Output>>()};
+    std::shared_ptr<mock::Output> mVirtualDisplay{std::make_shared<StrictMock<mock::Output>>()};
+    std::shared_ptr<mock::Output> mHalVirtualDisplay{std::make_shared<StrictMock<mock::Output>>()};
+
+    static constexpr PhysicalDisplayId kDisplayId1 = PhysicalDisplayId::fromPort(123u);
+    static constexpr PhysicalDisplayId kDisplayId2 = PhysicalDisplayId::fromPort(234u);
+    static constexpr GpuVirtualDisplayId kGpuVirtualDisplayId{789u};
+    static constexpr HalVirtualDisplayId kHalVirtualDisplayId{456u};
+
+    void SetUp() override {
+        EXPECT_CALL(*mDisplay1, getDisplayId)
+                .WillRepeatedly(Return(std::make_optional<DisplayId>(kDisplayId1)));
+        EXPECT_CALL(*mDisplay2, getDisplayId)
+                .WillRepeatedly(Return(std::make_optional<DisplayId>(kDisplayId2)));
+        EXPECT_CALL(*mVirtualDisplay, getDisplayId)
+                .WillRepeatedly(Return(std::make_optional<DisplayId>(kGpuVirtualDisplayId)));
+        EXPECT_CALL(*mHalVirtualDisplay, getDisplayId)
+                .WillRepeatedly(Return(std::make_optional<DisplayId>(kHalVirtualDisplayId)));
+    }
+
+    void setOutputs(std::initializer_list<std::shared_ptr<mock::Output>> outputs) {
+        for (auto& output : outputs) {
+            // If we call mEngine.present, prepare and present will be called on all the
+            // outputs in mRefreshArgs, but that's not the interesting part of the test.
+            EXPECT_CALL(*output, prepare(Ref(mRefreshArgs), _)).Times(1);
+            EXPECT_CALL(*output, present(Ref(mRefreshArgs)))
+                    .WillOnce(Return(ftl::yield<std::monostate>({})));
+
+            mRefreshArgs.outputs.push_back(std::move(output));
+        }
+    }
+};
+
+TEST_F(CompositionEngineOffloadTest, basic) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).WillOnce(Return(true));
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(1);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mDisplay2});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, dependsOnSupport) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(false));
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).Times(0);
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mDisplay2});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, dependsOnSupport2) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).WillOnce(Return(false));
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mDisplay2});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, dependsOnFlag) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).Times(0);
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).Times(0);
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, false);
+    setOutputs({mDisplay1, mDisplay2});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, oneDisplay) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).Times(0);
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, virtualDisplay) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mVirtualDisplay, supportsOffloadPresent).Times(0);
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(1);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mVirtualDisplay, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mDisplay2, mVirtualDisplay});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, virtualDisplay2) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mVirtualDisplay, supportsOffloadPresent).Times(0);
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mVirtualDisplay, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mVirtualDisplay});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, halVirtual) {
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mHalVirtualDisplay, supportsOffloadPresent).WillOnce(Return(true));
+
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(1);
+    EXPECT_CALL(*mHalVirtualDisplay, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mDisplay1, mHalVirtualDisplay});
+
+    mEngine.present(mRefreshArgs);
+}
+
+TEST_F(CompositionEngineOffloadTest, ordering) {
+    EXPECT_CALL(*mVirtualDisplay, supportsOffloadPresent).Times(0);
+    EXPECT_CALL(*mHalVirtualDisplay, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mDisplay1, supportsOffloadPresent).WillOnce(Return(true));
+    EXPECT_CALL(*mDisplay2, supportsOffloadPresent).WillOnce(Return(true));
+
+    EXPECT_CALL(*mVirtualDisplay, offloadPresentNextFrame).Times(0);
+    EXPECT_CALL(*mHalVirtualDisplay, offloadPresentNextFrame).Times(1);
+    EXPECT_CALL(*mDisplay1, offloadPresentNextFrame).Times(1);
+    EXPECT_CALL(*mDisplay2, offloadPresentNextFrame).Times(0);
+
+    SET_FLAG_FOR_TEST(flags::multithreaded_present, true);
+    setOutputs({mVirtualDisplay, mHalVirtualDisplay, mDisplay1, mDisplay2});
+
+    mEngine.present(mRefreshArgs);
+}
+
 } // namespace
 } // namespace android::compositionengine