diff --git a/tests/config/format-test/run-prettier.js b/tests/config/format-test/run-prettier.js
index 65be4737f..8549d2366 100644
--- a/tests/config/format-test/run-prettier.js
+++ b/tests/config/format-test/run-prettier.js
@@ -9,7 +9,19 @@ import {
 import { ensurePromise } from "./utilities.js";
 import visualizeEndOfLine from "./visualize-end-of-line.js";
 
+function unsetFilepath(options) {
+  const { filepath, ...restOptions } = options;
+
+  if (typeof filepath === "string" && filepath.endsWith(".unset-filepath")) {
+    return restOptions;
+  }
+
+  return options;
+}
+
 async function parse(input, options) {
+  options = unsetFilepath(options);
+
   const prettier = await getPrettier();
   const { ast } = await ensurePromise(
     prettier.__debug.parse(input, await loadPlugins(options), {
@@ -20,6 +32,8 @@ async function parse(input, options) {
 }
 
 async function format(input, options) {
+  options = unsetFilepath(options);
+
   const inputWithCursor = insertCursor(input, options.cursorOffset);
   const prettier = await getPrettier();
 
diff --git a/tests/format/misc/filename-matters/flow-ambient/__snapshots__/format.test.js.snap b/tests/format/misc/filename-matters/flow-ambient/__snapshots__/format.test.js.snap
index 57e3570b8..7c88ca287 100644
--- a/tests/format/misc/filename-matters/flow-ambient/__snapshots__/format.test.js.snap
+++ b/tests/format/misc/filename-matters/flow-ambient/__snapshots__/format.test.js.snap
@@ -1,29 +1,6 @@
 // Jest Snapshot v1, https://jestjs.io/docs/snapshot-testing
 
-exports[`ambient.js.flow format 1`] = `
-====================================options=====================================
-parsers: ["flow"]
-                                                      printWidth: 80 (default) |
-=====================================input======================================
-const foo: string;
-
-=====================================output=====================================
-const foo: string;
-
-================================================================================
-`;
-
-exports[`ambient.js.flow format[hermes] 1`] = `
-"missing initializer in const declaration (1:7)
-> 1 | const foo: string;
-    |       ^
-  2 |
-Cause: missing initializer in const declaration (1:6)
-const foo: string;
-      ^~~~~~~~~~~"
-`;
-
-exports[`snippet: #0 format 1`] = `
+exports[`snippet: const-without-initializer.js.flow format 1`] = `
 ====================================options=====================================
 parsers: ["flow"]
                                                       printWidth: 80 (default) |
@@ -35,7 +12,44 @@ const foo: string;
 ================================================================================
 `;
 
-exports[`snippet: #0 format[hermes] 1`] = `
+exports[`snippet: const-without-initializer.js.flow format[hermes] 1`] = `
+"missing initializer in const declaration (1:7)
+> 1 | const foo: string;
+    |       ^
+Cause: missing initializer in const declaration (1:6)
+const foo: string;
+      ^~~~~~~~~~~"
+`;
+
+exports[`snippet: const-without-initializer.unknown format[flow] 1`] = `
+"Const must be initialized (1:7)
+> 1 | const foo: string;
+    |       ^
+Cause: Const must be initialized (1:6)"
+`;
+
+exports[`snippet: const-without-initializer.unknown format[hermes] 1`] = `
+"missing initializer in const declaration (1:7)
+> 1 | const foo: string;
+    |       ^
+Cause: missing initializer in const declaration (1:6)
+const foo: string;
+      ^~~~~~~~~~~"
+`;
+
+exports[`snippet: const-without-initializer.unset-filepath format 1`] = `
+====================================options=====================================
+parsers: ["flow"]
+                                                      printWidth: 80 (default) |
+=====================================input======================================
+const foo: string;
+=====================================output=====================================
+const foo: string;
+
+================================================================================
+`;
+
+exports[`snippet: const-without-initializer.unset-filepath format[hermes] 1`] = `
 "missing initializer in const declaration (1:7)
 > 1 | const foo: string;
     |       ^
diff --git a/tests/format/misc/filename-matters/flow-ambient/ambient.js.flow b/tests/format/misc/filename-matters/flow-ambient/ambient.js.flow
deleted file mode 100644
index 6821c110c..000000000
--- a/tests/format/misc/filename-matters/flow-ambient/ambient.js.flow
+++ /dev/null
@@ -1 +0,0 @@
-const foo: string;
diff --git a/tests/format/misc/filename-matters/flow-ambient/format.test.js b/tests/format/misc/filename-matters/flow-ambient/format.test.js
index e382c0e71..ff5e0e469 100644
--- a/tests/format/misc/filename-matters/flow-ambient/format.test.js
+++ b/tests/format/misc/filename-matters/flow-ambient/format.test.js
@@ -1,11 +1,29 @@
+const tests = [
+  {
+    code: "const foo: string;",
+    baseFilename: "const-without-initializer",
+  },
+].flatMap(({ code, baseFilename }) =>
+  [".js.flow", ".unknown", ".unset-filepath"].map((extension) => {
+    const filename = `${baseFilename}${extension}`;
+    return {
+      name: filename,
+      code,
+      filename,
+    };
+  }),
+);
+
 runFormatTest(
   {
-    snippets: [
-      // Unknown filename
-      "const foo: string;",
-    ],
     importMeta: import.meta,
+    snippets: tests,
   },
   ["flow"],
-  { errors: { hermes: true } },
+  {
+    errors: {
+      flow: ["const-without-initializer.unknown"],
+      hermes: true,
+    },
+  },
 );