documentation: Writing Unit and Rendering Tests

Review URL: https://codereview.chromium.org/885133002

2 files changed, 67 insertions, 35 deletions

diff --git a/site/dev/contrib/submit.md b/site/dev/contrib/submit.md
index fcbcf2077d..a66e7271ac 100644
--- a/site/dev/contrib/submit.md
+++ b/site/dev/contrib/submit.md
@@ -32,41 +32,9 @@ Adding a unit test
 If you are willing to change Skia codebase, it's nice to add a test at the same
 time. Skia has a simple unittest framework so you can add a case to it.
 
-Test code is located under the 'tests' directory. Assuming we are adding
-tests/FooTest.cpp, The test code will look like:
+Test code is located under the 'tests' directory.
 
-<!--?prettify?-->
-~~~~
-/*
- * 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(TestFoo, reporter) {
-   int x = 2 * 3;
-   if (x != 6) {
-       ERRORF(reporter, "x should be 6, but is %d", x);
-       return;
-   }
-   REPORTER_ASSERT(reporter, 1 + 1 == 2);
-}
-~~~~
-
-And we need to add this new file to gyp/tests.gyp. Note that file names are
-sorted alphabetically.
-
-<!--?prettify?-->
-~~~~
-'sources': [
-  '../tests/AAClipTest.cpp'
-  '../tests/FooTest.cpp',
-  '../tests/XfermodeTest.cpp',
-],
-~~~~
+See [Writing Unit and Rendering Tests](tests) for details.
 
 Unit tests are best, but if your change touches rendering and you can't think of
 an automated way to verify the results, consider writing a GM test or a new page
@@ -74,7 +42,6 @@ of SampleApp. Also, if your change is the GPU code, you may not be able to write
 it as part of the standard unit test suite, but there are GPU-specific testing
 paths you can extend.
 
-
 Submitting a patch
 ------------------
 
diff --git a/site/dev/contrib/tests.md b/site/dev/contrib/tests.md
new file mode 100644
index 0000000000..fbe84dfeff
--- /dev/null
+++ b/site/dev/contrib/tests.md
@@ -0,0 +1,65 @@
+Writing Unit and Rendering Tests
+================================
+
+Writing a Unit Test
+-------------------
+
+1.  Add a file `tests/NewUnitTest.cpp`:
+
+    <!--?prettify lang=cc?-->
+
+        /*
+         * 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 a line to `gyp/tests.gypi`:
+
+        '../tests/NewUnitTest.cpp',
+
+3.  Recompile and run test:
+
+        ./gyp_skia
+        ninja -C out/Debug dm
+        out/Debug/dm --match NewUnitTest
+
+Writing a Rendering Test
+------------------------
+
+1.  Add a file `gm/newgmtest.cpp`:
+
+    <!--?prettify lang=cc?-->
+
+        /*
+         * 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 a line to `gyp/gmslides.gypi`:
+
+        '../gm/newgmtest.cpp',
+
+3.  Recompile and run test:
+
+        ./gyp_skia
+        ninja -C out/Debug dm
+        out/Debug/dm --match newgmtest