[gtk/fp16-tests: 2/2] tests: Add some fp16 tests

[Matthias Clasen <matthiasc src gnome org>]

commit fab82a7c252504a4520711b40aeb259d678309ae
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Jul 13 09:02:16 2021 -0400

    tests: Add some fp16 tests

 testsuite/gsk/half-float.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++
 testsuite/gsk/meson.build  |  3 +-
 2 files changed, 74 insertions(+), 1 deletion(-)
---
diff --git a/testsuite/gsk/half-float.c b/testsuite/gsk/half-float.c
new file mode 100644
index 0000000000..35dce9c1c8
--- /dev/null
+++ b/testsuite/gsk/half-float.c
@@ -0,0 +1,72 @@
+#include <gtk/gtk.h>
+
+#include "gsk/ngl/fp16private.h"
+
+static void
+test_constants (void)
+{
+  struct {
+    float f;
+    guint16 h;
+  } tests[] = {
+    { 0.0, FP16_ZERO },
+    { 1.0, FP16_ONE },
+    { -1.0, FP16_MINUS_ONE },
+  };
+
+  for (int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      float f[4];
+      guint16 h[4];
+
+      memset (f, 0, sizeof (f));
+      f[0] = tests[i].f;
+      float_to_half4 (f, h);
+      g_assert_cmpuint (h[0], ==, tests[i].h);
+
+
+      memset (h, 0, sizeof (h));
+      h[0] = tests[i].h;
+      half_to_float4 (h, f);
+      g_assert_cmpfloat (f[0], ==, tests[i].f);
+    }
+}
+
+static void
+test_roundtrip (void)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      float f[4];
+      float f2[4];
+      guint16 h[4];
+
+      do
+        {
+          /* generate a random float thats representable as fp16 */
+          memset (h, 0, sizeof (h));
+          h[0] = g_random_int_range (G_MININT16, G_MAXINT16);
+          half_to_float4 (h, f2);
+        }
+      while (!isnormal (f2[0])); /* skip nans and infs since they don't compare well */
+
+      memset (f, 0, sizeof (f));
+      f[0] = f2[0];
+
+      float_to_half4 (f, h);
+      half_to_float4 (h, f2);
+
+      g_assert_cmpfloat (f[0], ==, f2[0]);
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  (g_test_init) (&argc, &argv, NULL);
+
+  g_test_add_func ("/half-float/constants", test_constants);
+  g_test_add_func ("/half-float/roundtrip", test_roundtrip);
+
+  return g_test_run ();
+}
diff --git a/testsuite/gsk/meson.build b/testsuite/gsk/meson.build
index 8a15261ba0..4bdfc8ceaf 100644
--- a/testsuite/gsk/meson.build
+++ b/testsuite/gsk/meson.build
@@ -234,7 +234,8 @@ foreach t : tests
 endforeach
 
 internal_tests = [
-  ['diff']
+  [ 'diff' ],
+  [ 'half-float' ],
 ]
 
 foreach t : internal_tests