Add tests

src/harness/unittests/tsserverProjectSystem.ts

@@ -3493,6 +3493,30 @@ namespace ts.projectSystem {
         });
     });
 
+    describe("searching for config file", () => {
+        it("should stop at projectRootPath if given", () => {
+            const f1 = {
+                path: "/a/file1.ts",
+                content: ""
+            };
+            const configFile = {
+                path: "/tsconfig.json",
+                content: "{}"
+            };
+            const host = createServerHost([f1, configFile]);
+            const service = createProjectService(host);
+            service.openClientFile(f1.path, /*fileContent*/ undefined, /*scriptKind*/ undefined, "/a");
+
+            checkNumberOfConfiguredProjects(service, 0);
+            checkNumberOfInferredProjects(service, 1);
+
+            service.closeClientFile(f1.path);
+            service.openClientFile(f1.path);
+            checkNumberOfConfiguredProjects(service, 1);
+            checkNumberOfInferredProjects(service, 0);
+        });
+    });
+
     describe("cancellationToken", () => {
         it("is attached to request", () => {
             const f1 = {

src/server/editorServices.ts

@@ -1326,8 +1326,8 @@ namespace ts.server {
          * @param filename is absolute pathname
          * @param fileContent is a known version of the file content that is more up to date than the one on disk
          */
-        openClientFile(fileName: string, fileContent?: string, scriptKind?: ScriptKind): OpenConfiguredProjectResult {
-            return this.openClientFileWithNormalizedPath(toNormalizedPath(fileName), fileContent, scriptKind);
+        openClientFile(fileName: string, fileContent?: string, scriptKind?: ScriptKind, projectRootPath?: string): OpenConfiguredProjectResult {
+            return this.openClientFileWithNormalizedPath(toNormalizedPath(fileName), fileContent, scriptKind, /*hasMixedContent*/ false, projectRootPath ? toNormalizedPath(projectRootPath) : undefined);
         }
 
         openClientFileWithNormalizedPath(fileName: NormalizedPath, fileContent?: string, scriptKind?: ScriptKind, hasMixedContent?: boolean, projectRootPath?: NormalizedPath): OpenConfiguredProjectResult {