Fix some core:encoding/hxa stuff (error handling, header, max -> min)

Also add missing f16 case to core:reflect as_u64 & as_f64
Add tests for above & add previous tests missing from test/core/build.bat

tests/common/common.odin

@@ -4,6 +4,7 @@ package common
 import "core:testing"
 import "core:fmt"
 import "core:os"
+import "core:strings"
 
 TEST_count := 0
 TEST_fail  := 0
@@ -38,3 +39,37 @@ report :: proc(t: ^testing.T) {
 		fmt.printf("%v/%v tests successful.\n", TEST_count, TEST_count)
 	}
 }
+
+// Returns absolute path to `sub_path` where `sub_path` is within the "tests/" sub-directory of the Odin project root
+// and we're being run from the Odin project root or from a sub-directory of "tests/"
+// e.g. get_data_path("assets/blah") will return "/Odin_root/tests/assets/blah" if run within "/Odin_root",
+// "/Odin_root/tests" or "/Odin_root/tests/subdir" etc
+get_data_path :: proc(t: ^testing.T, sub_path: string) -> (data_path: string) {
+
+	cwd := os.get_current_directory()
+	defer delete(cwd)
+
+	when ODIN_OS == .Windows {
+		norm, was_allocation := strings.replace_all(cwd, "\\", "/")
+		if !was_allocation {
+			norm = strings.clone(norm)
+		}
+		defer delete(norm)
+	} else {
+		norm := cwd
+	}
+
+	last_index := strings.last_index(norm, "/tests/")
+	if last_index == -1 {
+		len := len(norm)
+		if len >= 6 && norm[len-6:] == "/tests" {
+			data_path = fmt.tprintf("%s/%s", norm, sub_path)
+		} else {
+			data_path = fmt.tprintf("%s/tests/%s", norm, sub_path)
+		}
+	} else {
+		data_path = fmt.tprintf("%s/tests/%s", norm[:last_index], sub_path)
+	}
+
+	return data_path
+}