Let the random number generator support float values

1 files changed, 85 insertions, 0 deletions

diff --git a/tests/support_tests.cpp b/tests/support_tests.cpp
index 7096eaf57..9e3140490 100644
--- a/tests/support_tests.cpp
+++ b/tests/support_tests.cpp
@@ -156,4 +156,89 @@ TEST(Support_next_uint, UnsignedInvalid)
 	EXPECT_NE(typeid(next_uint_t<uint64_t>), typeid(uint32_t));
 }
 
+template <typename T>
+void test_randomizer(const T min_value, const T max_value)
+{
+	// Ensure the range is valid
+	ASSERT_LT(min_value, max_value);
+
+	// Calculate one quarter of the range to roughly test the distribution
+	// of the generated values
+	const auto quarter_range = (max_value - min_value) / 4;
+	ASSERT_GT(quarter_range, 0);
+
+	// Calculate a value roughly 25% greater than min
+	const auto near_min = min_value + quarter_range;
+	ASSERT_GT(near_min, min_value);
+
+	// Calculate a value oughly 25% less than max
+	const auto near_max = max_value - quarter_range;
+	ASSERT_LT(near_max, max_value);
+
+	// State trackers of what we've found so far
+	bool found_near_middle = false;
+	bool found_near_min = false;
+	bool found_near_max = false;
+
+	// Create a random value generator
+	const auto generate_random_value = CreateRandomizer<T>(min_value, max_value);
+
+	constexpr auto max_iterations = 1000;
+
+	// Start generating and testing values
+	for (auto i = 0; i < max_iterations; ++i) {
+
+		const auto v = generate_random_value();
+		EXPECT_GE(v, min_value);
+		EXPECT_LE(v, max_value);
+
+		const auto values_span_range = found_near_middle && found_near_min && found_near_max;
+		if (values_span_range) {
+			break;
+		}
+		else if (v > near_min && v < near_max) {
+			found_near_middle = true;
+		}
+		else if (v < near_min) {
+			found_near_min = true;
+		} else if (v > near_max) {
+			found_near_max = true;
+		}
+	}
+	// We can only pass when values have been found near the middle, min, and max before we pass the test
+	ASSERT_TRUE(found_near_middle);
+	ASSERT_TRUE(found_near_min);
+	ASSERT_TRUE(found_near_max);
+}
+
+TEST(CreateRandomizer, RangeOfLetters)
+{
+	// Ensure we're dealing with the standard ASCII character values
+	ASSERT_EQ('A', 65);
+	ASSERT_EQ('z', 122);
+
+	test_randomizer('A', 'z');
+}
+
+TEST(CreateRandomizer, RangeOfFloats)
+{
+	// positive range
+	test_randomizer(1000.0f, 2000.0f);
+
+	// negative range
+	test_randomizer(-2000.0f, -1000.0f);
+
+	// postitive and negative range
+	test_randomizer(-32000.0f, 32000.0f);
+
+	// positive percent-as-ratio
+	test_randomizer(0.0f, 1.0f);
+
+	// negative percent-as-ratio
+	test_randomizer(-1.0f, 0.0f);
+
+	// postitive and negative percent-as-ratio
+	test_randomizer(-1.0f, 1.0f);
+}
+
 } // namespace