diff --git a/packages/backend-test-utils/package.json b/packages/backend-test-utils/package.json
index bc78e2b4e0..da626d3786 100644
--- a/packages/backend-test-utils/package.json
+++ b/packages/backend-test-utils/package.json
@@ -56,6 +56,7 @@
     "mysql2": "^2.2.5",
     "pg": "^8.3.0",
     "testcontainers": "^8.1.2",
+    "textextensions": "^5.16.0",
     "uuid": "^8.0.0"
   },
   "peerDependencies": {
diff --git a/packages/backend-test-utils/src/files/DirectoryMocker.ts b/packages/backend-test-utils/src/files/DirectoryMocker.ts
index 66a6823a2f..7bf23aa2de 100644
--- a/packages/backend-test-utils/src/files/DirectoryMocker.ts
+++ b/packages/backend-test-utils/src/files/DirectoryMocker.ts
@@ -16,8 +16,14 @@
 
 import { resolveSafeChildPath } from '@backstage/backend-common';
 import fs from 'fs-extra';
+import textextensions from 'textextensions';
 import { tmpdir as getTmpDir } from 'os';
-import { dirname, join as joinPath, resolve as resolvePath } from 'path';
+import {
+  dirname,
+  extname,
+  join as joinPath,
+  resolve as resolvePath,
+} from 'path';
 
 type MockEntry = {
   path: string;
@@ -37,6 +43,15 @@ interface DirectoryMockerOptions {
   root?: string;
 }
 
+interface DirectoryMockerGetContentOptions {
+  /**
+   * Whether or not to return files as text rather than buffers.
+   *
+   * Defaults to checking the file extension against a list of known text extensions.
+   */
+  shouldReadAsText?: boolean | ((path: string, buffer: Buffer) => boolean);
+}
+
 export class DirectoryMocker {
   static create(options?: DirectoryMockerOptions) {
     const root =
@@ -81,7 +96,14 @@ export class DirectoryMocker {
     }
   }
 
-  async getContent(): Promise<MockDirectory | undefined> {
+  async getContent(
+    options?: DirectoryMockerGetContentOptions,
+  ): Promise<MockDirectory | undefined> {
+    const shouldReadAsText =
+      (typeof options?.shouldReadAsText === 'boolean'
+        ? () => options?.shouldReadAsText
+        : options?.shouldReadAsText) ??
+      ((path: string) => textextensions.includes(extname(path).slice(1)));
     async function read(path: string): Promise<MockDirectory | undefined> {
       if (!(await fs.pathExists(path))) {
         return undefined;
@@ -98,7 +120,11 @@ export class DirectoryMocker {
               return [entry, await read(fullPath)];
             }
             const content = await fs.readFile(fullPath);
-            return [entry, content.toString('utf8')];
+
+            if (shouldReadAsText(fullPath, content)) {
+              return [entry, content.toString('utf8')];
+            }
+            return [entry, content];
           }),
         ),
       );
diff --git a/yarn.lock b/yarn.lock
index 83d9128534..86a011100e 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -3656,6 +3656,7 @@ __metadata:
     pg: ^8.3.0
     supertest: ^6.1.3
     testcontainers: ^8.1.2
+    textextensions: ^5.16.0
     uuid: ^8.0.0
   peerDependencies:
     "@types/jest": "*"
@@ -40458,10 +40459,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"textextensions@npm:^5.12.0, textextensions@npm:^5.13.0":
-  version: 5.14.0
-  resolution: "textextensions@npm:5.14.0"
-  checksum: 1f610ccf2a2c1445fb7156c23b5c8defd608c74e8047df18abd4b9ee44c74d29b453ba104d14c53c91f9026670f7c923114cd12200ee5ec458cc518fd0798c74
+"textextensions@npm:^5.12.0, textextensions@npm:^5.13.0, textextensions@npm:^5.16.0":
+  version: 5.16.0
+  resolution: "textextensions@npm:5.16.0"
+  checksum: d2abd5c962760046aa85d9ca542bd8bdb451370fc0a5e5f807aa80dd2f50175ec10d5ce9d28ae96968aaf6a1b1bea254cf4715f24852d0dcf29c6a60af7f793c
   languageName: node
   linkType: hard