Eliminate redundant lines and add tests

app.ts

@@ -1,6 +1,2 @@
 console.log("hello world");
 console.log("nice to meet you!!");
-console.log("hello world");
-console.log("nice to meet you!!");
-console.log("hello world");
-console.log("nice to meet you!!");

test/app.test.ts

@@ -0,0 +1,14 @@
+// Import a testing framework (e.g. Mocha, Jest, etc.)
+const assert = require('assert');
+const { execSync } = require('child_process');
+
+// Write a test suite for app.ts
+describe('app.ts', function() {
+  // Write a test case that checks that app.ts prints "hello world" and "nice to meet you!!" to the console
+  it('should print hello world and nice to meet you!!', function() {
+    // Run app.ts and capture the output
+    const output = execSync('node app.ts').toString();
+    // Assert that the output matches the expected strings
+    assert.match(output, /hello world\nnice to meet you!!\n/);
+  });
+});