Writing Skia Tests

We assume you have already synced Skia’s dependecies and set up Skia’s build system.

python tools/git-sync-deps
bin/gn gen out/Debug
bin/gn gen out/Release --args='is_debug=false'

Writing a Unit Test

  1. Add a file tests/NewUnitTest.cpp:

    /*
     * Copyright ........
     *
     * Use of this source code is governed by a BSD-style license
     * that can be found in the LICENSE file.
     */
    #include "Test.h"
    DEF_TEST(NewUnitTest, reporter) {
        if (1 + 1 != 2) {
            ERRORF(reporter, "%d + %d != %d", 1, 1, 2);
        }
        bool lifeIsGood = true;
        REPORTER_ASSERT(reporter, lifeIsGood);
    }
    
  2. Add NewUnitTest.cpp to gn/tests.gni.

  3. Recompile and run test:

    ninja -C out/Debug dm
    out/Debug/dm --match NewUnitTest
    

Writing a Rendering Test

  1. Add a file gm/newgmtest.cpp:

    /*
     * Copyright ........
     *
     * Use of this source code is governed by a BSD-style license
     * that can be found in the LICENSE file.
     */
    #include "gm.h"
    DEF_SIMPLE_GM(newgmtest, canvas, 128, 128) {
        canvas->clear(SK_ColorWHITE);
        SkPaint p;
        p.setStrokeWidth(2);
        canvas->drawLine(16, 16, 112, 112, p);
    }
    
  2. Add newgmtest.cpp to gn/gm.gni.

  3. Recompile and run test:

    ninja -C out/Debug dm
    out/Debug/dm --match newgmtest
    
  4. Run the GM inside SampleApp:

    ninja -C out/Debug SampleApp
    out/Debug/SampleApp --slide GM:newgmtest
    

Writing a Benchmark Test

  1. Add a file bench/FooBench.cpp:

    /*
     * Copyright ........
     *
     * Use of this source code is governed by a BSD-style license
     * that can be found in the LICENSE file.
     */
    #include "Benchmark.h"
    #include "SkCanvas.h"
    namespace {
    class FooBench : public Benchmark {
    public:
        FooBench() {}
        virtual ~FooBench() {}
    protected:
        const char* onGetName() override { return "Foo"; }
        SkIPoint onGetSize() override { return SkIPoint{100, 100}; }
        void onDraw(int loops, SkCanvas* canvas) override {
            while (loops-- > 0) {
                canvas->drawLine(0.0f, 0.0f, 100.0f, 100.0f, SkPaint());
            }
        }
    };
    }  // namespace
    DEF_BENCH(return new FooBench;)
    
  2. Add FooBench.cpp to gn/bench.gni.

  3. Recompile and run nanobench:

    ninja -C out/Release nanobench
    out/Release/nanobench --match Foo