diff --git a/test/tests.zig b/test/tests.zig
index ba713902ba..ad7e5d3652 100644
--- a/test/tests.zig
+++ b/test/tests.zig
@@ -158,6 +158,7 @@ pub fn addGenHTests(b: *build.Builder, test_filter: ?[]const u8) *build.Step {
         .step = b.step("test-gen-h", "Run the C header file generation tests"),
         .test_index = 0,
         .test_filter = test_filter,
+        .counter = 0,
     };
 
     gen_h.addCases(cases);
@@ -1104,6 +1105,7 @@ pub const GenHContext = struct {
     step: *build.Step,
     test_index: usize,
     test_filter: ?[]const u8,
+    counter: usize,
 
     const TestCase = struct {
         name: []const u8,
@@ -1206,7 +1208,11 @@ pub const GenHContext = struct {
     }
 
     pub fn add(self: *GenHContext, name: []const u8, source: []const u8, expected_lines: ...) void {
-        const tc = self.create("test.zig", name, source, expected_lines);
+        // MacOS appears to not be returning nanoseconds in fstat mtime,
+        // which causes fast test executions to think the file contents are unchanged.
+        const modified_name = self.b.fmt("test-{}.zig", self.counter);
+        self.counter += 1;
+        const tc = self.create(modified_name, name, source, expected_lines);
         self.addCase(tc);
     }