Fix DotNetCoreCLI@2 test command to fail when no project files found

Tasks/DotNetCoreCLIV2/Tests/L0.ts

@@ -208,16 +208,15 @@ describe('DotNetCoreExe Suite', function () {
         assert(tr.failed, 'task should have failed');
     });
 
-    it('test throws warning when zero match found', async () => {
+    it('test fails when zero match found', async () => {
         process.env["__projects__"] = "*fail*/project.json";
         process.env["__command__"] = "test";
         let tp = path.join(__dirname, 'validInputs.js')
         let tr: ttm.MockTestRunner = new ttm.MockTestRunner(tp);
         await tr.runAsync();
 
         assert(tr.invokedToolCount == 0, 'should not have invoked tool');
-        assert(tr.succeeded, 'task should have succeeded');
-        assert(tr.warningIssues && tr.warningIssues.length, 'Should have thrown a warning in the stream');
+        assert(tr.failed, 'task should have failed');
     });
 
     it('publish works with explicit project files setting modifyoutput to false', async () => {

Tasks/DotNetCoreCLIV2/dotnetcore.ts

@@ -178,8 +178,7 @@ export class dotNetExe {
         // Use empty string when no project file is specified to operate on the current directory
         const projectFiles = this.getProjectFiles();
         if (projectFiles.length === 0) {
-            tl.warning(tl.loc('noProjectFilesFound'));
-            return;
+            throw tl.loc('noProjectFilesFound');
         }
 
         const failedProjects: string[] = [];