diff --git a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
index 8382d456f5..7731f5fea6 100644
--- a/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
+++ b/packages/compiler-cli/src/ngtsc/file_system/testing/src/mock_file_system.ts
@@ -119,7 +119,7 @@ export abstract class MockFileSystem implements FileSystem {
   }
 
   ensureDir(path: AbsoluteFsPath): void {
-    const segments = this.splitPath(path).map(segment => this.getCanonicalPath(segment));
+    const segments = this.splitPath(path);
     let current: Folder = this._fileTree;
 
     // Convert the root folder to a canonical empty string `''` (on Windows it would be `'C:'`).
@@ -212,29 +212,12 @@ export abstract class MockFileSystem implements FileSystem {
   protected abstract splitPath<T extends PathString>(path: T): string[];
 
   dump(): Folder {
-    return this.cloneFolder(this._fileTree);
+    return cloneFolder(this._fileTree);
   }
   init(folder: Folder): void {
-    this._fileTree = this.cloneFolder(folder);
+    this._fileTree = cloneFolder(folder);
   }
 
-  private cloneFolder(folder: Folder): Folder {
-    const clone: Folder = {};
-    for (const path in folder) {
-      const item = folder[path];
-      const canonicalPath = this.getCanonicalPath(path);
-      if (isSymLink(item)) {
-        clone[canonicalPath] = new SymLink(this.getCanonicalPath(item.path));
-      } else if (isFolder(item)) {
-        clone[canonicalPath] = this.cloneFolder(item);
-      } else {
-        clone[canonicalPath] = folder[path];
-      }
-    }
-    return clone;
-  }
-
-
   protected findFromPath(path: AbsoluteFsPath, options?: {followSymLinks: boolean}): FindResult {
     const followSymLinks = !!options && options.followSymLinks;
     const segments = this.splitPath(path);
@@ -246,7 +229,7 @@ export abstract class MockFileSystem implements FileSystem {
     segments[0] = '';
     let current: Entity|null = this._fileTree;
     while (segments.length) {
-      current = current[this.getCanonicalPath(segments.shift()!)];
+      current = current[segments.shift()!];
       if (current === undefined) {
         return {path, entity: null};
       }
@@ -269,14 +252,10 @@ export abstract class MockFileSystem implements FileSystem {
   }
 
   protected splitIntoFolderAndFile(path: AbsoluteFsPath): [AbsoluteFsPath, string] {
-    const segments = this.splitPath(this.getCanonicalPath(path));
+    const segments = this.splitPath(path);
     const file = segments.pop()!;
     return [path.substring(0, path.length - file.length - 1) as AbsoluteFsPath, file];
   }
-
-  protected getCanonicalPath<T extends string>(p: T): T {
-    return this.isCaseSensitive() ? p : p.toLowerCase() as T;
-  }
 }
 export interface FindResult {
   path: AbsoluteFsPath;
@@ -321,3 +300,18 @@ export function isSymLink(item: Entity|null): item is SymLink {
 export function isFolder(item: Entity|null): item is Folder {
   return item !== null && !isFile(item) && !isSymLink(item);
 }
+
+function cloneFolder(folder: Folder): Folder {
+  const clone: Folder = {};
+  for (const path in folder) {
+    const item = folder[path];
+    if (isSymLink(item)) {
+      clone[path] = new SymLink(item.path);
+    } else if (isFolder(item)) {
+      clone[path] = cloneFolder(item);
+    } else {
+      clone[path] = folder[path];
+    }
+  }
+  return clone;
+}