Tests for Schema Compare utils file (#10822)

* Introduced ApiWrapper for testability

* Added tests for coverage of utils.ts

* Addressed comments

extensions/schema-compare/src/common/apiWrapper.ts

@@ -0,0 +1,48 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the Source EULA. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as vscode from 'vscode';
+import * as azdata from 'azdata';
+
+/**
+ * Wrapper class to act as a facade over VSCode and Data APIs and allow us to test / mock callbacks into
+ * this API from our code
+ */
+export class ApiWrapper {
+	public openConnectionDialog(providers?: string[],
+		initialConnectionProfile?: azdata.IConnectionProfile,
+		connectionCompletionOptions?: azdata.IConnectionCompletionOptions): Thenable<azdata.connection.Connection> {
+		return azdata.connection.openConnectionDialog(providers, initialConnectionProfile, connectionCompletionOptions);
+	}
+
+	public registerCommand(command: string, callback: (...args: any[]) => any, thisArg?: any): vscode.Disposable {
+		return vscode.commands.registerCommand(command, callback, thisArg);
+	}
+
+	public getUriForConnection(connectionId: string): Thenable<string> {
+		return azdata.connection.getUriForConnection(connectionId);
+	}
+
+	public getConnections(activeConnectionsOnly?: boolean): Thenable<azdata.connection.ConnectionProfile[]> {
+		return azdata.connection.getConnections(activeConnectionsOnly);
+	}
+
+	public connect(connectionProfile: azdata.IConnectionProfile, saveConnection?: boolean, showDashboard?: boolean): Thenable<azdata.ConnectionResult> {
+		return azdata.connection.connect(connectionProfile, saveConnection, showDashboard);
+	}
+
+	public showErrorMessage(message: string, ...items: string[]): Thenable<string | undefined> {
+		return vscode.window.showErrorMessage(message, ...items);
+	}
+
+	public showWarningMessage(message: string, options?: vscode.MessageOptions, ...items: string[]): Thenable<string | undefined> {
+		if (options) {
+			return vscode.window.showWarningMessage(message, options, ...items);
+		}
+		else {
+			return vscode.window.showWarningMessage(message, ...items);
+		}
+	}
+}