Motown: Add new Ratio and LinearFunction classes to media/common/cpp.

services/media/common/test/linear_function_test.cc

Index: services/media/common/test/linear_function_test.cc
diff --git a/services/media/common/test/linear_function_test.cc b/services/media/common/test/linear_function_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b2ab53df380a6e41fb1f931d26c28ba90370e046
--- /dev/null
+++ b/services/media/common/test/linear_function_test.cc
@@ -0,0 +1,226 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/services/media/common/cpp/linear_function.h"
+#include "services/media/common/test/test_base.h"
+
+namespace mojo {
+namespace media {
+namespace {
+
+class LinearFunctionTest : public TestBase {
+ public:
+  // Verifies that a LinearFunction instantiated in three different ways with
+  // the given arguments has the expected properties.
+  void VerifyBasics(int64_t domain_basis,
+                    int64_t range_basis,
+                    uint32_t domain_delta,
+                    uint32_t range_delta) {
+    LinearFunction under_test_1(domain_basis, range_basis, domain_delta,
+                                range_delta);
+    VerifyBasics(under_test_1, domain_basis, range_basis, domain_delta,
+                 range_delta);
+
+    LinearFunction under_test_2(domain_basis, range_basis,
+                                Ratio(range_delta, domain_delta));
+    VerifyBasics(under_test_2, domain_basis, range_basis, domain_delta,
+                 range_delta);
+
+    LinearFunction under_test_3(Ratio(range_delta, domain_delta));
+    VerifyBasics(under_test_3, 0, 0, domain_delta, range_delta);
+
+    EXPECT_EQ(under_test_1, under_test_1);
+    EXPECT_EQ(under_test_1, under_test_2);
+    EXPECT_EQ(under_test_2, under_test_1);
+    EXPECT_EQ(under_test_2, under_test_2);
+
+    if (domain_basis == 0 && range_basis == 0) {
+      EXPECT_EQ(under_test_1, under_test_3);
+      EXPECT_EQ(under_test_2, under_test_3);
+      EXPECT_EQ(under_test_3, under_test_1);
+      EXPECT_EQ(under_test_3, under_test_2);
+    } else {
+      EXPECT_NE(under_test_1, under_test_3);
+      EXPECT_NE(under_test_2, under_test_3);
+      EXPECT_NE(under_test_3, under_test_1);
+      EXPECT_NE(under_test_3, under_test_2);
+    }
+  }
+
+  // Verifies that the given LinearFunction instantiated with the given
+  // arguments has the expected properties.
+  void VerifyBasics(const LinearFunction& under_test,
+                    int64_t domain_basis,
+                    int64_t range_basis,
+                    uint32_t domain_delta,
+                    uint32_t range_delta) {
+    Ratio::Reduce(&range_delta, &domain_delta);
+    EXPECT_EQ(domain_basis, under_test.domain_basis());
+    EXPECT_EQ(range_basis, under_test.range_basis());
+    EXPECT_EQ(domain_delta, under_test.domain_delta());
+    EXPECT_EQ(range_delta, under_test.range_delta());
+    EXPECT_EQ(domain_delta, under_test.slope().denominator());
+    EXPECT_EQ(range_delta, under_test.slope().numerator());
+  }
+
+  // Verifies that the inverse of a LinearFunction instantiated in three
+  // different ways with the given arguments has the expected properties.
+  void VerifyInverse(int64_t domain_basis,
+                     int64_t range_basis,
+                     uint32_t domain_delta,
+                     uint32_t range_delta) {
+    LinearFunction under_test_1(domain_basis, range_basis, domain_delta,
+                                range_delta);
+    VerifyBasics(under_test_1.Inverse(), range_basis, domain_basis, range_delta,
+                 domain_delta);
+
+    LinearFunction under_test_2(domain_basis, range_basis,
+                                Ratio(range_delta, domain_delta));
+    VerifyBasics(under_test_2.Inverse(), range_basis, domain_basis, range_delta,
+                 domain_delta);
+
+    LinearFunction under_test_3(Ratio(range_delta, domain_delta));
+    VerifyBasics(under_test_3.Inverse(), 0, 0, range_delta, domain_delta);
+  }
+
+  // Verifies that LinearFunction::Apply, in its various forms, works as
+  // expected for the given arguments.
+  void VerifyApply(int64_t domain_basis,
+                   int64_t range_basis,
+                   uint32_t domain_delta,
+                   uint32_t range_delta,
+                   int64_t domain_input,
+                   int64_t expected_result) {
+    // Verify the static method.
+    EXPECT_EQ(
+        expected_result,
+        LinearFunction::Apply(domain_basis, range_basis,
+                              Ratio(range_delta, domain_delta), domain_input));
+
+    // Verify the instance method.
+    LinearFunction under_test(domain_basis, range_basis, domain_delta,
+                              range_delta);
+    EXPECT_EQ(expected_result, under_test.Apply(domain_input));
+
+    // Verify the operator.
+    EXPECT_EQ(expected_result, under_test(domain_input));
+  }
+
+  // Verifies that LinearFunction::ApplyInverse, in its various forms, works as
+  // expected for the given arguments.
+  void VerifyApplyInverse(int64_t domain_basis,
+                          int64_t range_basis,
+                          uint32_t domain_delta,
+                          uint32_t range_delta,
+                          int64_t range_input,
+                          int64_t expected_result) {
+    // Verify the static method.
+    EXPECT_EQ(expected_result,
+              LinearFunction::ApplyInverse(domain_basis, range_basis,
+                                           Ratio(range_delta, domain_delta),
+                                           range_input));
+
+    // Verify the instance method.
+    LinearFunction under_test(domain_basis, range_basis, domain_delta,
+                              range_delta);
+    EXPECT_EQ(expected_result, under_test.ApplyInverse(range_input));
+  }
+
+  // Verifies that LinearFunction::Compose works as expected with the given
+  // inputs.
+  void VerifyCompose(const LinearFunction& a,
+                     const LinearFunction& b,
+                     bool exact,
+                     const LinearFunction& expected_result) {
+    // Verify the static method.
+    EXPECT_EQ(expected_result, LinearFunction::Compose(a, b, exact));
+  }
+};
+
+// Tests LinearFunction basics for various instantiation arguments.
+TEST_F(LinearFunctionTest, Basics) {
+  VerifyBasics(0, 0, 1, 0);
+  VerifyBasics(0, 0, 1, 1);
+  VerifyBasics(1, 1, 10, 10);
+  VerifyBasics(1234, 5678, 4321, 8765);
+  VerifyBasics(-1234, 5678, 4321, 8765);
+  VerifyBasics(-1234, -5678, 4321, 8765);
+  VerifyBasics(1234, -5678, 4321, 8765);
+}
+
+// Tests LinearFunction::Inverse.
+TEST_F(LinearFunctionTest, Inverse) {
+  VerifyInverse(0, 0, 1, 1);
+  VerifyInverse(1, 1, 10, 10);
+  VerifyInverse(1234, 5678, 4321, 8765);
+  VerifyInverse(-1234, 5678, 4321, 8765);
+  VerifyInverse(-1234, -5678, 4321, 8765);
+  VerifyInverse(1234, -5678, 4321, 8765);
+}
+
+// Tests LinearFunction::Apply in its variations.
+TEST_F(LinearFunctionTest, Apply) {
+  VerifyApply(0, 0, 1, 0, 0, 0);
+  VerifyApply(0, 0, 1, 0, 1000, 0);
+  VerifyApply(0, 1234, 1, 0, 0, 1234);
+  VerifyApply(0, 1234, 1, 0, 1000, 1234);
+  VerifyApply(0, 1234, 1, 0, -1000, 1234);
+  VerifyApply(0, -1234, 1, 0, 0, -1234);
+  VerifyApply(0, -1234, 1, 0, 1000, -1234);
+  VerifyApply(0, -1234, 1, 0, -1000, -1234);
+  VerifyApply(0, 0, 1, 1, 0, 0);
+  VerifyApply(0, 0, 1, 1, 1000, 1000);
+  VerifyApply(0, 1234, 1, 1, 0, 1234);
+  VerifyApply(0, 1234, 1, 1, 1000, 2234);
+  VerifyApply(0, 1234, 1, 1, -1000, 234);
+  VerifyApply(0, -1234, 1, 1, 0, -1234);
+  VerifyApply(0, -1234, 1, 1, 1000, -234);
+  VerifyApply(0, -1234, 1, 1, -1000, -2234);
+  VerifyApply(10, 0, 1, 0, 0, 0);
+  VerifyApply(10, 0, 1, 1, 0, -10);
+  VerifyApply(-10, 0, 1, 0, 0, 0);
+  VerifyApply(-10, 0, 1, 1, 0, 10);
+  VerifyApply(0, 1234, 2, 1, 0, 1234);
+  VerifyApply(0, 1234, 2, 1, 1234, 1234 + 1234 / 2);
+  VerifyApply(0, 1234, 1, 2, 1234, 1234 + 1234 * 2);
+}
+
+// Tests LinearFunction::Apply in its variations.
+TEST_F(LinearFunctionTest, ApplyInverse) {
+  VerifyApplyInverse(0, 0, 1, 1, 0, 0);
+  VerifyApplyInverse(0, 0, 1, 1, 1000, 1000);
+  VerifyApplyInverse(0, 1234, 1, 1, 1234, 0);
+  VerifyApplyInverse(0, 1234, 1, 1, 2234, 1000);
+  VerifyApplyInverse(0, 1234, 1, 1, 234, -1000);
+  VerifyApplyInverse(0, -1234, 1, 1, -1234, 0);
+  VerifyApplyInverse(0, -1234, 1, 1, -234, 1000);
+  VerifyApplyInverse(0, -1234, 1, 1, -2234, -1000);
+  VerifyApplyInverse(10, 0, 1, 1, -10, 0);
+  VerifyApplyInverse(-10, 0, 1, 1, 10, 0);
+  VerifyApplyInverse(0, 1234, 2, 1, 1234, 0);
+  VerifyApplyInverse(0, 1234, 2, 1, 1234 + 1234 / 2, 1234);
+  VerifyApplyInverse(0, 1234, 1, 2, 1234 + 1234 * 2, 1234);
+}
+
+// Tests LinearFunction::Compose.
+TEST_F(LinearFunctionTest, Compose) {
+  VerifyCompose(LinearFunction(0, 0, 1, 0), LinearFunction(0, 0, 1, 0), true,
+                LinearFunction(0, 0, 1, 0));
+  VerifyCompose(LinearFunction(0, 0, 1, 1), LinearFunction(0, 0, 1, 1), true,
+                LinearFunction(0, 0, 1, 1));
+  VerifyCompose(LinearFunction(1, 0, 1, 1), LinearFunction(0, 0, 1, 1), true,
+                LinearFunction(0, -1, 1, 1));
+  VerifyCompose(LinearFunction(10, 10, 1, 1), LinearFunction(0, 0, 1, 1), true,
+                LinearFunction(0, 0, 1, 1));
+  VerifyCompose(LinearFunction(0, 0, 1, 2), LinearFunction(0, 0, 1, 2), true,
+                LinearFunction(0, 0, 1, 4));
+  VerifyCompose(LinearFunction(0, 0, 2, 1), LinearFunction(0, 0, 2, 1), true,
+                LinearFunction(0, 0, 4, 1));
+  VerifyCompose(LinearFunction(0, 0, 2, 1), LinearFunction(0, 0, 1, 2), true,
+                LinearFunction(0, 0, 1, 1));
+}
+
+}  // namespace
+}  // namespace media
+}  // namespace mojo