Convert Checksum test to DEF_TEST() macro.

tests/ChecksumTest.cpp

Index: tests/ChecksumTest.cpp
diff --git a/tests/ChecksumTest.cpp b/tests/ChecksumTest.cpp
index c2f2be2ae62d528c23a1ff3b0d5a2e4dac76a34a..11e1f43bb4721732a59284205a14d550a7da2bfc 100644
--- a/tests/ChecksumTest.cpp
+++ b/tests/ChecksumTest.cpp
@@ -1,142 +1,53 @@
-
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-#include "Test.h"
 
 #include "SkChecksum.h"
-
-// Word size that is large enough to hold results of any checksum type.
-typedef uint64_t checksum_result;
-
-namespace skiatest {
-    class ChecksumTestClass : public Test {
-    public:
-        static Test* Factory(void*) {return SkNEW(ChecksumTestClass); }
-    protected:
-        virtual void onGetName(SkString* name) { name->set("Checksum"); }
-        virtual void onRun(Reporter* reporter) {
-            this->fReporter = reporter;
-            RunTest();
-        }
-    private:
-        enum Algorithm {
-            kSkChecksum,
-            kMurmur3,
-        };
-
-        // Call Compute(data, size) on the appropriate checksum algorithm,
-        // depending on this->fWhichAlgorithm.
-        checksum_result ComputeChecksum(const char *data, size_t size) {
-            switch(fWhichAlgorithm) {
-            case kSkChecksum:
-                REPORTER_ASSERT_MESSAGE(fReporter,
-                                        reinterpret_cast<uintptr_t>(data) % 4 == 0,
-                                        "test data pointer is not 32-bit aligned");
-                REPORTER_ASSERT_MESSAGE(fReporter, SkIsAlign4(size),
-                                        "test data size is not 32-bit aligned");
-                return SkChecksum::Compute(reinterpret_cast<const uint32_t *>(data), size);
-            case kMurmur3:
-                REPORTER_ASSERT_MESSAGE(fReporter,
-                                        reinterpret_cast<uintptr_t>(data) % 4 == 0,
-                                        "test data pointer is not 32-bit aligned");
-                REPORTER_ASSERT_MESSAGE(fReporter, SkIsAlign4(size),
-                                        "test data size is not 32-bit aligned");
-                return SkChecksum::Murmur3(reinterpret_cast<const uint32_t *>(data), size);
-            default:
-                SkString message("fWhichAlgorithm has unknown value ");
-                message.appendf("%d", fWhichAlgorithm);
-                fReporter->reportFailed(message);
-            }
-            // we never get here
-            return 0;
-        }
-
-        // Confirm that the checksum algorithm (specified by fWhichAlgorithm)
-        // generates the same results if called twice over the same data.
-        void TestChecksumSelfConsistency(size_t buf_size) {
-            SkAutoMalloc storage(buf_size);
-            char* ptr = reinterpret_cast<char *>(storage.get());
-
-            REPORTER_ASSERT(fReporter,
-                            GetTestDataChecksum(8, 0) ==
-                            GetTestDataChecksum(8, 0));
-            REPORTER_ASSERT(fReporter,
-                            GetTestDataChecksum(8, 0) !=
-                            GetTestDataChecksum(8, 1));
-
-            sk_bzero(ptr, buf_size);
-            checksum_result prev = 0;
-
-            // assert that as we change values (from 0 to non-zero) in
-            // our buffer, we get a different value
-            for (size_t i = 0; i < buf_size; ++i) {
-                ptr[i] = (i & 0x7f) + 1; // need some non-zero value here
-
-                // Try checksums of different-sized chunks, but always
-                // 32-bit aligned and big enough to contain all the
-                // nonzero bytes.  (Remaining bytes will still be zero
-                // from the initial sk_bzero() call.)
-                size_t checksum_size = (((i/4)+1)*4);
-                REPORTER_ASSERT(fReporter, checksum_size <= buf_size);
-
-                checksum_result curr = ComputeChecksum(ptr, checksum_size);
-                REPORTER_ASSERT(fReporter, prev != curr);
-                checksum_result again = ComputeChecksum(ptr, checksum_size);
-                REPORTER_ASSERT(fReporter, again == curr);
-                prev = curr;
-            }
-        }
-
-        // Return the checksum of a buffer of bytes 'len' long.
-        // The pattern of values within the buffer will be consistent
-        // for every call, based on 'seed'.
-        checksum_result GetTestDataChecksum(size_t len, char seed=0) {
-            SkAutoMalloc storage(len);
-            char* start = reinterpret_cast<char *>(storage.get());
-            char* ptr = start;
-            for (size_t i = 0; i < len; ++i) {
-                *ptr++ = ((seed+i) & 0x7f);
-            }
-            checksum_result result = ComputeChecksum(start, len);
-            return result;
-        }
-
-        void RunTest() {
-            const Algorithm algorithms[] = { kSkChecksum, kMurmur3 };
-            for (size_t i = 0; i < SK_ARRAY_COUNT(algorithms); i++) {
-                fWhichAlgorithm = algorithms[i];
-
-                // Test self-consistency of checksum algorithms.
-                TestChecksumSelfConsistency(128);
-
-                // Test checksum results that should be consistent across
-                // versions and platforms.
-                REPORTER_ASSERT(fReporter, ComputeChecksum(NULL, 0) == 0);
-
-                const bool colision1 = GetTestDataChecksum(128) == GetTestDataChecksum(256);
-                const bool colision2 = GetTestDataChecksum(132) == GetTestDataChecksum(260);
-                if (fWhichAlgorithm == kSkChecksum) {
-                    // TODO: note the weakness exposed by these collisions...
-                    // We need to improve the SkChecksum algorithm.
-                    // We would prefer that these asserts FAIL!
-                    // Filed as https://code.google.com/p/skia/issues/detail?id=981
-                    // ('SkChecksum algorithm allows for way too many collisions')
-                    REPORTER_ASSERT(fReporter, colision1);
-                    REPORTER_ASSERT(fReporter, colision2);
-                } else {
-                    REPORTER_ASSERT(fReporter, !colision1);
-                    REPORTER_ASSERT(fReporter, !colision2);
-                }
-            }
+#include "SkRandom.h"
+#include "Test.h"
+#include "TestClassDef.h"
+
+
+// Murmur3 has an optional third seed argument, so we wrap it to fit a uniform type.
+static uint32_t murmur_noseed(const uint32_t* d, size_t l) { return SkChecksum::Murmur3(d, l); }
+
+#define ASSERT(x) REPORTER_ASSERT(r, x)
+
+DEF_TEST(Checksum, r) {
+    // Algorithms to test.  They're currently all uint32_t(const uint32_t*, size_t).
+    typedef uint32_t(*algorithmProc)(const uint32_t*, size_t);
+    const algorithmProc kAlgorithms[] = { &SkChecksum::Compute, &murmur_noseed };
+
+    // Put 128 random bytes into two identical buffers.  Any multiple of 4 will do.
+    const size_t kBytes = 128;
+    SkRandom rand;
+    uint32_t data[kBytes/4], tweaked[kBytes/4];

[bungeman-skia, 2014/01/09 17:08:20]

Totally not really needed, but you were just making me assert that a constant
that needed to be a power of 2 actually was, so maybe we should
SK_COMPILE_ASSERT here that kBytes is divisible by 4?

[mtklein, 2014/01/09 17:11:37]

Since this is sort of silly, I have solved it in a silly way, by wrapping
SkAlign4 around 128.

+    for (size_t i = 0; i < SK_ARRAY_COUNT(tweaked); ++i) {
+        data[i] = tweaked[i] = rand.nextU();
+    }
+
+    // Test each algorithm.
+    for (size_t i = 0; i < SK_ARRAY_COUNT(kAlgorithms); ++i) {
+        const algorithmProc algorithm = kAlgorithms[i];
+
+        // Hash of NULL is always 0.
+        ASSERT(algorithm(NULL, 0) == 0);
+
+        const uint32_t hash = algorithm(data, kBytes);
+        // Should be deterministic.
+        ASSERT(hash == algorithm(data, kBytes));
+
+        // Changing any single element should change the hash.
+        for (size_t j = 0; j < SK_ARRAY_COUNT(tweaked); ++j) {
+            const uint32_t saved = tweaked[j];
+            tweaked[j] = rand.nextU();
+            const uint32_t tweakedHash = algorithm(tweaked, kBytes);
+            ASSERT(tweakedHash != hash);
+            ASSERT(tweakedHash == algorithm(tweaked, kBytes));
+            tweaked[j] = saved;
         }
-
-        Reporter* fReporter;
-        Algorithm fWhichAlgorithm;
-    };
-
-    static TestRegistry gReg(ChecksumTestClass::Factory);
+    }
 }