From 384aad6906d0abf6fb689ca09d082259f9b6a082 Mon Sep 17 00:00:00 2001
From: Sheetal Nandi <shkamat@microsoft.com>
Date: Tue, 6 Feb 2018 10:50:32 -0800
Subject: [PATCH] Add test case for file change happening as part of file
 create and delete

---
 src/harness/unittests/tscWatchMode.ts     | 32 +++++++++++++++++++++++
 src/harness/virtualFileSystemWithWatch.ts | 18 ++++++++++---
 2 files changed, 46 insertions(+), 4 deletions(-)

diff --git a/src/harness/unittests/tscWatchMode.ts b/src/harness/unittests/tscWatchMode.ts
index b6d3099dc77..45cabc2be0e 100644
--- a/src/harness/unittests/tscWatchMode.ts
+++ b/src/harness/unittests/tscWatchMode.ts
@@ -1719,6 +1719,38 @@ namespace ts.tscWatch {
                 return [files[0]];
             }
         });
+
+        it("file is deleted and created as part of change", () => {
+            const projectLocation = "/home/username/project";
+            const file: FileOrFolder = {
+                path: `${projectLocation}/app/file.ts`,
+                content: "var a = 10;"
+            };
+            const fileJs = `${projectLocation}/app/file.js`;
+            const configFile: FileOrFolder = {
+                path: `${projectLocation}/tsconfig.json`,
+                content: JSON.stringify({
+                    "include": [
+                        "app/**/*.ts"
+                    ]
+                })
+            };
+            const files = [file, configFile, libFile];
+            const host = createWatchedSystem(files, { currentDirectory: projectLocation, useCaseSensitiveFileNames: true });
+            createWatchOfConfigFile("tsconfig.json", host);
+            verifyProgram();
+
+            file.content += "var b = 10;";
+
+            host.reloadFS(files, { invokeFileDeleteCreateAsPartInsteadOfChange: true });
+            host.runQueuedTimeoutCallbacks();
+            verifyProgram();
+
+            function verifyProgram() {
+                assert.isTrue(host.fileExists(fileJs));
+                assert.equal(host.readFile(fileJs), file.content + "\n");
+            }
+        });
     });
 
     describe("tsc-watch module resolution caching", () => {
diff --git a/src/harness/virtualFileSystemWithWatch.ts b/src/harness/virtualFileSystemWithWatch.ts
index 381917d71c7..8545e193ae4 100644
--- a/src/harness/virtualFileSystemWithWatch.ts
+++ b/src/harness/virtualFileSystemWithWatch.ts
@@ -246,8 +246,12 @@ interface Array<T> {}`
     }
 
     export interface ReloadWatchInvokeOptions {
+        /** Invokes the directory watcher for the parent instead of the file changed */
         invokeDirectoryWatcherInsteadOfFileChanged: boolean;
+        /** When new file is created, do not invoke watches for it */
         ignoreWatchInvokedWithTriggerAsFileCreate: boolean;
+        /** Invoke the file delete, followed by create instead of file changed */
+        invokeFileDeleteCreateAsPartInsteadOfChange: boolean;
     }
 
     export class TestServerHost implements server.ServerHost, FormatDiagnosticsHost, ModuleResolutionHost {
@@ -315,12 +319,18 @@ interface Array<T> {}`
                         if (isString(fileOrDirectory.content)) {
                             // Update file
                             if (currentEntry.content !== fileOrDirectory.content) {
-                                currentEntry.content = fileOrDirectory.content;
-                                if (options && options.invokeDirectoryWatcherInsteadOfFileChanged) {
-                                    this.invokeDirectoryWatcher(getDirectoryPath(currentEntry.fullPath), currentEntry.fullPath);
+                                if (options && options.invokeFileDeleteCreateAsPartInsteadOfChange) {
+                                    this.removeFileOrFolder(currentEntry, returnFalse);
+                                    this.ensureFileOrFolder(fileOrDirectory);
                                 }
                                 else {
-                                    this.invokeFileWatcher(currentEntry.fullPath, FileWatcherEventKind.Changed);
+                                    currentEntry.content = fileOrDirectory.content;
+                                    if (options && options.invokeDirectoryWatcherInsteadOfFileChanged) {
+                                        this.invokeDirectoryWatcher(getDirectoryPath(currentEntry.fullPath), currentEntry.fullPath);
+                                    }
+                                    else {
+                                        this.invokeFileWatcher(currentEntry.fullPath, FileWatcherEventKind.Changed);
+                                    }
                                 }
                             }
                         }