Add tests for `core:math/rand`

tests/core/math/rand/test_core_math_rand.odin

@@ -0,0 +1,35 @@
+package test_core_math_rand
+
+import "core:math/rand"
+import "core:testing"
+
+@test
+test_default_rand_determinism :: proc(t: ^testing.T) {
+	rand.reset(13)
+	first_value := rand.int127()
+	rand.reset(13)
+	second_value := rand.int127()
+
+	testing.expect(t, first_value == second_value, "Context default random number generator is non-deterministic.")
+}
+
+@test
+test_default_rand_determinism_user_set :: proc(t: ^testing.T) {
+	rng_state_1 := rand.create(13)
+	rng_state_2 := rand.create(13)
+
+	rng_1 := rand.default_random_generator(&rng_state_1)
+	rng_2 := rand.default_random_generator(&rng_state_2)
+
+	first_value, second_value: i128
+	{
+		context.random_generator = rng_1
+		first_value = rand.int127()
+	}
+	{
+		context.random_generator = rng_2
+		second_value = rand.int127()
+	}
+
+	testing.expect(t, first_value == second_value, "User-set default random number generator is non-deterministic.")
+}

tests/core/normal.odin

@@ -24,6 +24,7 @@ download_assets :: proc() {
 @(require) import "math/big"
 @(require) import "math/linalg/glsl"
 @(require) import "math/noise"
+@(require) import "math/rand"
 @(require) import "mem"
 @(require) import "net"
 @(require) import "odin"