Install karma peer dependencies on test init (#2693)

* implicitly install karma-<testingFramework>'s peer dependencies on test init command

* add exception handling when installing packages already present in the project

* log warning instead of throwing errors when a package's name couldn't be determined when installed using the node-package-manager service

Author: petekanev

lib/commands/test-init.ts

@@ -37,6 +37,25 @@ class TestInitCommand implements ICommand {
 				'save-dev': true,
 				optional: false,
 			});
+
+			const modulePath = path.join(projectDir, "node_modules", mod);
+			const modulePackageJsonPath = path.join(modulePath, "package.json");
+			const modulePackageJsonContent = this.$fs.readJson(modulePackageJsonPath);
+			const modulePeerDependencies = modulePackageJsonContent.peerDependencies || {};
+
+			for (let peerDependency in modulePeerDependencies) {
+				let dependencyVersion = modulePeerDependencies[peerDependency] || "*";
+
+				// catch errors when a peerDependency is already installed
+				// e.g karma is installed; karma-jasmine depends on karma and will try to install it again
+				try {
+					await this.$npm.install(`${peerDependency}@${dependencyVersion}`, projectDir, {
+						'save-dev': true
+					});
+				} catch (e) {
+					this.$logger.error(e.message);
+				}
+			}
 		}
 
 		await this.$pluginsService.add('nativescript-unit-test-runner', this.$projectData);

lib/node-package-manager.ts

@@ -76,10 +76,10 @@ export class NodePackageManager implements INodePackageManager {
 		let diff = dependencyDiff.concat(devDependencyDiff);
 
 		if (diff.length <= 0 && dependenciesBefore.length === dependenciesAfter.length && packageName !== pathToSave) {
-			this.$errors.failWithoutHelp(`The plugin ${packageName} is already installed`);
+			this.$logger.warn(`The plugin ${packageName} is already installed`);
 		}
 		if (diff.length <= 0 && dependenciesBefore.length !== dependenciesAfter.length) {
-			this.$errors.failWithoutHelp(`Couldn't install package correctly`);
+			this.$logger.warn(`Couldn't install package ${packageName} correctly`);
 		}
 
 		return diff;