add exception handling when installing packages already present in the project

Author: petekanev

lib/commands/test-init.ts

@@ -45,9 +45,16 @@ class TestInitCommand implements ICommand {
 
 			for (let peerDependency in modulePeerDependencies) {
 				let dependencyVersion = modulePeerDependencies[peerDependency] || "*";
-				await this.$npm.install(`${peerDependency}@${dependencyVersion}`, projectDir, {
-					'save-dev': true
-				});
+
+				// catch errors when a peerDependency is already installed
+				// e.g karma is installed; karma-jasmine depends on karma and will try to install it again
+				try {
+					await this.$npm.install(`${peerDependency}@${dependencyVersion}`, projectDir, {
+						'save-dev': true
+					});
+				} catch (e) {
+					this.$logger.info(e.message);
+				}
 			}
 		}