diff --git a/src/harness/virtualFileSystemWithWatch.ts b/src/harness/virtualFileSystemWithWatch.ts
index 8830e1cb01a..c034258533b 100644
--- a/src/harness/virtualFileSystemWithWatch.ts
+++ b/src/harness/virtualFileSystemWithWatch.ts
@@ -30,11 +30,11 @@ interface Array<T> { length: number; [n: number]: T; }`
         inodeWatching?: boolean;
     }
 
-    export function createWatchedSystem(fileOrFolderList: readonly FileOrFolderOrSymLink[], params?: TestServerHostCreationParameters): TestServerHost {
+    export function createWatchedSystem(fileOrFolderList: FileOrFolderOrSymLinkMap | readonly FileOrFolderOrSymLink[], params?: TestServerHostCreationParameters): TestServerHost {
         return new TestServerHost(fileOrFolderList, params);
     }
 
-    export function createServerHost(fileOrFolderList: readonly FileOrFolderOrSymLink[], params?: TestServerHostCreationParameters): TestServerHost {
+    export function createServerHost(fileOrFolderList: FileOrFolderOrSymLinkMap | readonly FileOrFolderOrSymLink[], params?: TestServerHostCreationParameters): TestServerHost {
         const host = new TestServerHost(fileOrFolderList, params);
         // Just like sys, patch the host to use writeFile
         patchWriteFileEnsuringDirectory(host);
@@ -59,6 +59,9 @@ interface Array<T> { length: number; [n: number]: T; }`
     }
 
     export type FileOrFolderOrSymLink = File | Folder | SymLink;
+    export interface FileOrFolderOrSymLinkMap {
+        [path: string]: string | Omit<FileOrFolderOrSymLink, "path">;
+    }
     export function isFile(fileOrFolderOrSymLink: FileOrFolderOrSymLink): fileOrFolderOrSymLink is File {
         return isString((fileOrFolderOrSymLink as File).content);
     }
@@ -289,7 +292,6 @@ interface Array<T> { length: number; [n: number]: T; }`
         useCaseSensitiveFileNames: boolean;
         executingFilePath: string;
         currentDirectory: string;
-        fileOrFolderorSymLinkList: readonly FileOrFolderOrSymLink[];
         newLine?: string;
         useWindowsStylePaths?: boolean;
         environmentVariables?: ESMap<string, string>;
@@ -326,7 +328,7 @@ interface Array<T> { length: number; [n: number]: T; }`
         private readonly inodes?: ESMap<Path, number>;
         watchDirectory: HostWatchDirectory;
         constructor(
-            fileOrFolderorSymLinkList: readonly FileOrFolderOrSymLink[],
+            fileOrFolderorSymLinkList: FileOrFolderOrSymLinkMap | readonly FileOrFolderOrSymLink[],
             {
                 useCaseSensitiveFileNames, executingFilePath, currentDirectory,
                 newLine, windowsStyleRoot, environmentVariables,
@@ -415,16 +417,27 @@ interface Array<T> { length: number; [n: number]: T; }`
             return new Date(this.time);
         }
 
-        private reloadFS(fileOrFolderOrSymLinkList: readonly FileOrFolderOrSymLink[]) {
+        private reloadFS(fileOrFolderOrSymLinkList: FileOrFolderOrSymLinkMap | readonly FileOrFolderOrSymLink[]) {
             Debug.assert(this.fs.size === 0);
-            const filesOrFoldersToLoad: readonly FileOrFolderOrSymLink[] = !this.windowsStyleRoot ? fileOrFolderOrSymLinkList :
-                fileOrFolderOrSymLinkList.map<FileOrFolderOrSymLink>(f => {
-                    const result = clone(f);
-                    result.path = this.getHostSpecificPath(f.path);
-                    return result;
-                });
-            for (const fileOrDirectory of filesOrFoldersToLoad) {
-                this.ensureFileOrFolder(fileOrDirectory);
+            if (isArray(fileOrFolderOrSymLinkList)) {
+                fileOrFolderOrSymLinkList.forEach(f => this.ensureFileOrFolder(!this.windowsStyleRoot ?
+                    f :
+                    { ...f, path: this.getHostSpecificPath(f.path) }
+                ));
+            }
+            else {
+                for (const key in fileOrFolderOrSymLinkList) {
+                    if (hasProperty(fileOrFolderOrSymLinkList, key)) {
+                        const path = this.getHostSpecificPath(key);
+                        const value = fileOrFolderOrSymLinkList[key];
+                        if (isString(value)) {
+                            this.ensureFileOrFolder({ path, content: value });
+                        }
+                        else {
+                            this.ensureFileOrFolder({ path, ...value });
+                        }
+                    }
+                }
             }
         }
 
diff --git a/src/testRunner/unittests/tscWatch/emit.ts b/src/testRunner/unittests/tscWatch/emit.ts
index 217d4c059a5..8c9ec7150b1 100644
--- a/src/testRunner/unittests/tscWatch/emit.ts
+++ b/src/testRunner/unittests/tscWatch/emit.ts
@@ -6,21 +6,12 @@ namespace ts.tscWatch {
                 scenario,
                 subScenario: `emit with outFile or out setting/${subScenario}`,
                 commandLineArgs: ["--w", "-p", "/a/tsconfig.json"],
-                sys: () => {
-                    const config: File = {
-                        path: "/a/tsconfig.json",
-                        content: JSON.stringify({ compilerOptions: { out, outFile } })
-                    };
-                    const f1: File = {
-                        path: "/a/a.ts",
-                        content: "let x = 1"
-                    };
-                    const f2: File = {
-                        path: "/a/b.ts",
-                        content: "let y = 1"
-                    };
-                    return createWatchedSystem([f1, f2, config, libFile]);
-                },
+                sys: () => createWatchedSystem({
+                    "/a/a.ts": "let x = 1",
+                    "/a/b.ts": "let y = 1",
+                    "/a/tsconfig.json": JSON.stringify({ compilerOptions: { out, outFile } }),
+                    [libFile.path]: libFile.content,
+                }),
                 changes: [
                     {
                         caption: "Make change in the file",
diff --git a/src/testRunner/unittests/tscWatch/helpers.ts b/src/testRunner/unittests/tscWatch/helpers.ts
index 70b79aba0b6..92ad07cd8d8 100644
--- a/src/testRunner/unittests/tscWatch/helpers.ts
+++ b/src/testRunner/unittests/tscWatch/helpers.ts
@@ -432,7 +432,7 @@ namespace ts.tscWatch {
         return sys;
     }
 
-    export function createSystemWithSolutionBuild(solutionRoots: readonly string[], files: readonly TestFSWithWatch.FileOrFolderOrSymLink[], params?: TestFSWithWatch.TestServerHostCreationParameters) {
+    export function createSystemWithSolutionBuild(solutionRoots: readonly string[], files: TestFSWithWatch.FileOrFolderOrSymLinkMap | readonly TestFSWithWatch.FileOrFolderOrSymLink[], params?: TestFSWithWatch.TestServerHostCreationParameters) {
         return solutionBuildWithBaseline(createWatchedSystem(files, params), solutionRoots);
     }
 }
diff --git a/src/testRunner/unittests/tscWatch/watchEnvironment.ts b/src/testRunner/unittests/tscWatch/watchEnvironment.ts
index 72081fdb0c7..5cc92d55b5f 100644
--- a/src/testRunner/unittests/tscWatch/watchEnvironment.ts
+++ b/src/testRunner/unittests/tscWatch/watchEnvironment.ts
@@ -587,22 +587,18 @@ namespace ts.tscWatch {
                 scenario,
                 subScenario: `fsWatch/when using file watching thats on inode`,
                 commandLineArgs: ["-w", "--extendedDiagnostics"],
-                sys: () => {
-                    const configFile: File = {
-                        path: `${projectRoot}/tsconfig.json`,
-                        content: JSON.stringify({ watchOptions: { watchFile: "useFsEvents" }, files: ["foo.d.ts", "main.ts"] })
-                    };
-                    const main: File = {
-                        path: `${projectRoot}/main.ts`,
-                        content: `import { foo } from "./foo"; foo();`
-                    };
-                    const foo: File = {
-                        path: `${projectRoot}/foo.d.ts`,
-                        content: `export function foo(): string;`
-                    };
-                    const files = [libFile, main, foo, configFile];
-                    return createWatchedSystem(files, { currentDirectory: projectRoot, inodeWatching: true });
-                },
+                sys: () => createWatchedSystem(
+                    {
+                        [libFile.path]: libFile.content,
+                        [`${projectRoot}/main.ts`]: `import { foo } from "./foo"; foo();`,
+                        [`${projectRoot}/foo.d.ts`]: `export function foo(): string;`,
+                        [`${projectRoot}/tsconfig.json`]: JSON.stringify({ watchOptions: { watchFile: "useFsEvents" }, files: ["foo.d.ts", "main.ts"] }),
+                    },
+                    {
+                        currentDirectory: projectRoot,
+                        inodeWatching: true
+                    }
+                ),
                 changes: [
                     {
                         caption: "Replace file with rename event that introduces error",