SDL: Test: Add Floor tests to math.

From b3faebb8a83e9fead34ee7b61cce2a280a5f7e12 Mon Sep 17 00:00:00 2001
From: Pierre Wendling <[EMAIL REDACTED]>
Date: Wed, 4 May 2022 12:40:24 -0400
Subject: [PATCH] Test: Add Floor tests to math.

---
 test/testautomation_math.c | 109 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 108 insertions(+), 1 deletion(-)

diff --git a/test/testautomation_math.c b/test/testautomation_math.c
index 5ac6ea3f801..ab8213f2d46 100644
--- a/test/testautomation_math.c
+++ b/test/testautomation_math.c
@@ -5,6 +5,113 @@
 #include "SDL.h"
 #include "SDL_test.h"
 
-static const SDLTest_TestCaseReference* mathTests[] = {NULL};
+/* ================= Test Case Implementation ================== */
+
+/* SDL_floor tests functions */
+
+/**
+ * \brief Checks edge cases (0 and infinity) for themselves.
+ */
+static int floor_edgeCases(void* args) {
+  static const double edge_cases[] = {INFINITY, -INFINITY, 0.0, -0.0};
+  for (size_t i = 0; i < SDL_arraysize(edge_cases); i++) {
+    const double result = SDL_floor(edge_cases[i]);
+    SDLTest_AssertCheck(result == edge_cases[i],
+                        "Floor(%.1f), expected %.1f, got %.1f", edge_cases[i],
+                        edge_cases[i], result);
+  }
+  return TEST_COMPLETED;
+}
+
+/**
+ * \brief Checks the NaN case.
+ */
+static int floor_nanCase(void* args) {
+  SDLTest_AssertCheck(isnan(SDL_floor(NAN)), "Floor(nan), expected nan");
+  return TEST_COMPLETED;
+}
+
+/**
+ * \brief Checks round values (x.0) for themselves
+ */
+static int floor_roundNumbersCases(void* args) {
+  static const double round_cases[] = {1.0,   -1.0,   15.0,   -15.0,
+                                       125.0, -125.0, 1024.0, -1024.0};
+  for (size_t i = 0; i < SDL_arraysize(round_cases); i++) {
+    const double result = SDL_floor(round_cases[i]);
+    SDLTest_AssertCheck(result == round_cases[i],
+                        "Floor(%.1f), expected %.1f, got %.1f", round_cases[i],
+                        round_cases[i], result);
+  }
+  return TEST_COMPLETED;
+}
+
+/**
+ * \brief Checks a set of fractions
+ */
+static int floor_fractionCases(void* args) {
+  static const struct {
+    double input, expected;
+  } frac_cases[] = {{1.0 / 2.0, 0.0},        {-1.0 / 2.0, -1.0},
+                    {4.0 / 3.0, 1.0},        {-4.0 / 3.0, -2.0},
+                    {76.0 / 7.0, 10.0},      {-76.0 / 7.0, -11.0},
+                    {535.0 / 8.0, 66.0},     {-535.0 / 8.0, -67.0},
+                    {19357.0 / 53.0, 365.0}, {-19357.0 / 53.0, -366.0}};
+  for (size_t i = 0; i < SDL_arraysize(frac_cases); i++) {
+    const double result = SDL_floor(frac_cases[i].input);
+    SDLTest_AssertCheck(result == frac_cases[i].expected,
+                        "Floor(%f), expected %.1f, got %f", frac_cases[i].input,
+                        frac_cases[i].expected, result);
+  }
+  return TEST_COMPLETED;
+}
+
+/**
+ * \brief Checks a range of values between 0 and UINT32_MAX
+ */
+static int floor_rangeTest(void* args) {
+  static const Uint32 ITERATIONS = 10000000;
+  static const Uint32 STEP = UINT32_MAX / ITERATIONS;
+  double test_value = 0.0;
+  SDLTest_AssertPass("Floor: Testing a range of %u values with %u steps",
+                     ITERATIONS, STEP);
+  for (Uint32 i = 0; i < ITERATIONS; i++, test_value += STEP) {
+    /* These are tested elsewhere */
+    if (isnan(test_value) || isinf(test_value)) {
+      continue;
+    }
+
+    const double result = SDL_floor(test_value);
+    if (result != test_value) { /* Only log failures to save performances */
+      SDLTest_AssertPass("Floor(%.1f), expected %.1f, got %.1f", test_value,
+                         test_value, result);
+      return TEST_ABORTED;
+    }
+  }
+  return TEST_COMPLETED;
+}
+
+/* ================= Test References ================== */
+
+/* SDL_floor test cases */
+
+static const SDLTest_TestCaseReference floorTest1 = {
+    (SDLTest_TestCaseFp)floor_edgeCases, "floor_edgeCases",
+    "Check positive and negative infinity and 0", TEST_ENABLED};
+static const SDLTest_TestCaseReference floorTest2 = {
+    (SDLTest_TestCaseFp)floor_nanCase, "floor_nanCase",
+    "Check the NaN special case", TEST_ENABLED};
+static const SDLTest_TestCaseReference floorTest3 = {
+    (SDLTest_TestCaseFp)floor_roundNumbersCases, "floor_roundNumberCases",
+    "Check a set of round numbers", TEST_ENABLED};
+static const SDLTest_TestCaseReference floorTest4 = {
+    (SDLTest_TestCaseFp)floor_fractionCases, "floor_fractionCases",
+    "Check a set of fractions", TEST_ENABLED};
+static const SDLTest_TestCaseReference floorTest5 = {
+    (SDLTest_TestCaseFp)floor_rangeTest, "floor_rangeTest",
+    "Check a range of positive integer", TEST_ENABLED};
+
+static const SDLTest_TestCaseReference* mathTests[] = {
+    &floorTest1, &floorTest2, &floorTest3, &floorTest4, &floorTest5, NULL};
 
 SDLTest_TestSuiteReference mathTestSuite = {"Math", NULL, mathTests, NULL};