1 files changed, 59 insertions, 0 deletions
diff --git a/test/style/functions.cpp b/test/style/functions.cpp
new file mode 100644
index 0000000000..d19d2ea88e
--- /dev/null
+++ b/test/style/functions.cpp
@@ -0,0 +1,59 @@
+#include <iostream>
+#include "../fixtures/util.hpp"
+
+#include <mbgl/style/function.hpp>
+#include <mbgl/style/style_calculation_parameters.hpp>
+
+using namespace mbgl;
+
+TEST(Function, Constant) {
+    EXPECT_EQ(2.0f, mbgl::Function<float>(2).evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(3.8f, mbgl::Function<float>(3.8).evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(22.0f, mbgl::Function<float>(22).evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(2.0f, mbgl::Function<float>(2).evaluate(StyleCalculationParameters(4)));
+    EXPECT_EQ(3.8f, mbgl::Function<float>(3.8).evaluate(StyleCalculationParameters(4)));
+    EXPECT_EQ(22.0f, mbgl::Function<float>(22).evaluate(StyleCalculationParameters(4)));
+    EXPECT_EQ(2.0f, mbgl::Function<float>(2).evaluate(StyleCalculationParameters(22)));
+    EXPECT_EQ(3.8f, mbgl::Function<float>(3.8).evaluate(StyleCalculationParameters(22)));
+    EXPECT_EQ(22.0f, mbgl::Function<float>(22).evaluate(StyleCalculationParameters(22)));
+}
+
+TEST(Function, Stops) {
+    // Explicit constant slope in fringe regions.
+    mbgl::Function<float> slope_1({ { 0, 1.5 }, { 6, 1.5 }, { 8, 3 }, { 22, 3 } }, 1.75);
+    EXPECT_EQ(1.5, slope_1.evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(1.5, slope_1.evaluate(StyleCalculationParameters(4)));
+    EXPECT_EQ(1.5, slope_1.evaluate(StyleCalculationParameters(6)));
+    ASSERT_FLOAT_EQ(2.0454545454545454, slope_1.evaluate(StyleCalculationParameters(7)));
+    EXPECT_EQ(3.0, slope_1.evaluate(StyleCalculationParameters(8)));
+    EXPECT_EQ(3.0, slope_1.evaluate(StyleCalculationParameters(9)));
+    EXPECT_EQ(3.0, slope_1.evaluate(StyleCalculationParameters(15)));
+    EXPECT_EQ(3.0, slope_1.evaluate(StyleCalculationParameters(22)));
+
+
+    // Test constant values in fringe regions.
+    mbgl::Function<float> slope_2({ { 6, 1.5 }, { 8, 3 } }, 1.75);
+    EXPECT_EQ(1.5, slope_2.evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(1.5, slope_2.evaluate(StyleCalculationParameters(4)));
+    EXPECT_EQ(1.5, slope_2.evaluate(StyleCalculationParameters(6)));
+    ASSERT_FLOAT_EQ(2.0454545454545454, slope_2.evaluate(StyleCalculationParameters(7)));
+    EXPECT_EQ(3.0, slope_2.evaluate(StyleCalculationParameters(8)));
+    EXPECT_EQ(3.0, slope_2.evaluate(StyleCalculationParameters(9)));
+    EXPECT_EQ(3.0, slope_2.evaluate(StyleCalculationParameters(15)));
+    EXPECT_EQ(3.0, slope_2.evaluate(StyleCalculationParameters(22)));
+
+    // Test no values.
+    mbgl::Function<float> slope_3({}, 1.75);
+    EXPECT_EQ(1, slope_3.evaluate(StyleCalculationParameters(2)));
+    EXPECT_EQ(1, slope_3.evaluate(StyleCalculationParameters(6)));
+    EXPECT_EQ(1, slope_3.evaluate(StyleCalculationParameters(12)));
+
+
+    // Explicit constant slope in fringe regions.
+    mbgl::Function<float> slope_4({ { 0, 2 }, { 8, 10 } }, 1);
+    EXPECT_EQ(2, slope_4.evaluate(StyleCalculationParameters(0)));
+    EXPECT_EQ(3, slope_4.evaluate(StyleCalculationParameters(1)));
+    EXPECT_EQ(4, slope_4.evaluate(StyleCalculationParameters(2)));
+    EXPECT_EQ(4.75, slope_4.evaluate(StyleCalculationParameters(2.75)));
+    EXPECT_EQ(10, slope_4.evaluate(StyleCalculationParameters(8)));
+}