add failing test for runtime arena edge case

tests/core/Makefile

@@ -20,7 +20,8 @@ all: c_libc_test \
 	 reflect_test \
 	 slice_test \
 	 strings_test \
-	 thread_test
+	 thread_test \
+	 runtime_test
 
 download_test_assets:
 	$(PYTHON) download_assets.py
@@ -84,3 +85,6 @@ fmt_test:
 
 thread_test:
 	$(ODIN) run thread -out:test_core_thread
+
+runtime_test:
+	$(ODIN) run runtime -out:test_core_runtime

tests/core/build.bat

@@ -95,3 +95,8 @@ echo ---
 echo Running core:thread tests
 echo ---
 %PATH_TO_ODIN% run thread %COMMON% %COLLECTION% -out:test_core_thread.exe || exit /b
+
+echo ---
+echo Running core:runtime tests
+echo ---
+%PATH_TO_ODIN% run runtime %COMMON% %COLLECTION% -out:test_core_runtime.exe || exit /b

tests/core/runtime/test_core_runtime.odin

@@ -0,0 +1,61 @@
+package test_core_runtime
+
+import "core:fmt"
+import "core:intrinsics"
+import "core:mem"
+import "core:os"
+import "core:reflect"
+import "core:runtime"
+import "core:testing"
+
+TEST_count := 0
+TEST_fail  := 0
+
+when ODIN_TEST {
+	expect_value :: testing.expect_value
+} else {
+	expect_value :: proc(t: ^testing.T, value, expected: $T, loc := #caller_location) -> bool where intrinsics.type_is_comparable(T) {
+		TEST_count += 1
+		ok := value == expected || reflect.is_nil(value) && reflect.is_nil(expected)
+		if !ok {
+			TEST_fail += 1
+			fmt.printf("[%v] expected %v, got %v\n", loc, expected, value)
+		}
+		return ok
+	}
+}
+
+main :: proc() {
+	t := testing.T{}
+
+	test_temp_allocator_alignment_boundary(&t)
+	test_temp_allocator_big_alloc_and_alignment(&t)
+
+	fmt.printf("%v/%v tests successful.\n", TEST_count - TEST_fail, TEST_count)
+	if TEST_fail > 0 {
+		os.exit(1)
+	}
+}
+
+// Tests that having space for the allocation, but not for the allocation and alignment
+// is handled correctly.
+@(test)
+test_temp_allocator_alignment_boundary :: proc(t: ^testing.T) {
+	arena: runtime.Arena
+	context.allocator = runtime.arena_allocator(&arena)
+
+	_, _ = mem.alloc(int(runtime.DEFAULT_ARENA_GROWING_MINIMUM_BLOCK_SIZE)-120)
+	_, err := mem.alloc(112, 32)
+	expect_value(t, err, nil)
+}
+
+// Tests that big allocations with big alignments are handled correctly.
+@(test)
+test_temp_allocator_big_alloc_and_alignment :: proc(t: ^testing.T) {
+	arena: runtime.Arena
+	context.allocator = runtime.arena_allocator(&arena)
+
+	mappy: map[[8]int]int
+    err := reserve(&mappy, 50000)
+	expect_value(t, err, nil)
+}