Fix tests to use text when useText method is used

Author: sheetalkamat

src/server/scriptInfo.ts

@@ -128,7 +128,7 @@ export class TextStorage {
     }
 
     /** Public for testing */
-    public useText(newText?: string) {
+    public useText(newText: string) {
         this.svc = undefined;
         this.text = newText;
         this.lineMap = undefined;

src/testRunner/unittests/tsserver/textStorage.ts

@@ -25,7 +25,6 @@ describe("unittests:: tsserver:: Text storage", () => {
         const ts2 = new ts.server.TextStorage(host, getDummyScriptInfo(ts.server.asNormalizedPath(f.path)));
 
         ts1.useScriptVersionCache_TestOnly();
-        ts2.useText();
 
         const lineMap = ts.computeLineStarts(f.content);
 
@@ -64,7 +63,7 @@ describe("unittests:: tsserver:: Text storage", () => {
         ts1.edit(0, 5, "   ");
         assert.isTrue(ts1.hasScriptVersionCache_TestOnly(), "have script version cache - 1");
 
-        ts1.useText();
+        ts1.useText("");
         assert.isFalse(ts1.hasScriptVersionCache_TestOnly(), "should not have script version cache - 2");
 
         ts1.getAbsolutePositionAndLineText(0);