2 files changed, 64 insertions, 1 deletions
diff --git a/tests/core/Makefile b/tests/core/Makefile
index 77d4b85a0..919262f85 100644
--- a/tests/core/Makefile
+++ b/tests/core/Makefile
@@ -2,7 +2,8 @@ ODIN=../../odin
 PYTHON=$(shell which python3)
 
 all: download_test_assets image_test compress_test strings_test hash_test crypto_test noise_test encoding_test \
-	 math_test linalg_glsl_math_test filepath_test reflect_test os_exit_test i18n_test match_test c_libc_test net_test
+	 math_test linalg_glsl_math_test filepath_test reflect_test os_exit_test i18n_test match_test c_libc_test net_test \
+	 fmt_test
 
 download_test_assets:
 	$(PYTHON) download_assets.py
@@ -57,3 +58,6 @@ c_libc_test:
 
 net_test:
 	$(ODIN) run net -out:test_core_net
+
+fmt_test:
+	$(ODIN) run fmt -out:test_core_fmt
diff --git a/tests/core/fmt/test_core_fmt.odin b/tests/core/fmt/test_core_fmt.odin
new file mode 100644
index 000000000..4459af609
--- /dev/null
+++ b/tests/core/fmt/test_core_fmt.odin
@@ -0,0 +1,59 @@
+package test_core_fmt
+
+import "core:fmt"
+import "core:os"
+import "core:testing"
+import "core:mem"
+
+TEST_count := 0
+TEST_fail  := 0
+
+when ODIN_TEST {
+	expect  :: testing.expect
+	log     :: testing.log
+} else {
+	expect  :: proc(t: ^testing.T, condition: bool, message: string, loc := #caller_location) {
+		TEST_count += 1
+		if !condition {
+			TEST_fail += 1
+			fmt.printf("[%v] %v\n", loc, message)
+			return
+		}
+	}
+	log     :: proc(t: ^testing.T, v: any, loc := #caller_location) {
+		fmt.printf("[%v] ", loc)
+		fmt.printf("log: %v\n", v)
+	}
+}
+
+main :: proc() {
+	t := testing.T{}
+	test_fmt_memory(&t)
+
+	fmt.printf("%v/%v tests successful.\n", TEST_count - TEST_fail, TEST_count)
+	if TEST_fail > 0 {
+		os.exit(1)
+	}
+}
+
+test_fmt_memory :: proc(t: ^testing.T) {
+	check :: proc(t: ^testing.T, exp: string, format: string, args: ..any, loc := #caller_location) {
+		got := fmt.tprintf(format, ..args)
+		expect(t, got == exp, fmt.tprintf("(%q, %v): %q != %q", format, args, got, exp), loc)
+	}
+
+	check(t, "5b",        "%m",    5)
+	check(t, "5B",        "%M",    5)
+	check(t, "-5B",       "%M",    -5)
+	check(t, "3.00kib",   "%m",    mem.Kilobyte * 3)
+	check(t, "3kib",      "%.0m",  mem.Kilobyte * 3)
+	check(t, "3KiB",      "%.0M",  mem.Kilobyte * 3)
+	check(t, "3.000 mib", "%#.3m", mem.Megabyte * 3)
+	check(t, "3.50 gib",  "%#m",   u32(mem.Gigabyte * 3.5))
+	check(t, "01tib",     "%5.0m", mem.Terabyte)
+	check(t, "-1tib",     "%5.0m", -mem.Terabyte)
+	check(t, "2.50 pib",  "%#5.m", uint(mem.Petabyte * 2.5))
+	check(t, "1.00 EiB",  "%#M",   mem.Exabyte)
+	check(t, "255 B",     "%#M",   u8(255))
+	check(t, "0b",        "%m",    u8(0))
+}