feat: add "deno init" subcommand (#15469)

This adds an init subcommand to that creates a project starter similar to cargo init.

```
$ deno init my_project
Project initialized
Run these commands to get started:
  cd my_project
  deno run main.ts
  deno run main_test.ts
$ deno run main.ts
Add 2 + 3 5
$ cat main.ts
export function add(a: number, b: number): number {
  return a + b;
}
if (import.meta.main) {
  console.log("Add 2 + 3", add(2, 3));
}
$ cat main_test.ts
import { assertEquals } from "https://deno.land/std@0.151.0/testing/asserts.ts";
import { add } from "./main.ts";
Deno.test(function addTest() {
    assertEquals(add(2, 3), 5);
});
```

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 110 insertions, 0 deletions

diff --git a/cli/tests/integration/init_tests.rs b/cli/tests/integration/init_tests.rs
new file mode 100644
index 000000000..a7a54f06b
--- /dev/null
+++ b/cli/tests/integration/init_tests.rs
@@ -0,0 +1,110 @@
+// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
+
+use std::process::Stdio;
+use test_util as util;
+use test_util::TempDir;
+use util::assert_contains;
+
+#[test]
+fn init_subcommand_without_dir() {
+  let temp_dir = TempDir::new();
+  let cwd = temp_dir.path();
+  let deno_dir = util::new_deno_dir();
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .arg("init")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  let stdout = String::from_utf8(output.stdout).unwrap();
+  assert_contains!(stdout, "Project initialized");
+  assert!(!stdout.contains("cd"));
+  assert_contains!(stdout, "deno run main.ts");
+  assert_contains!(stdout, "deno test");
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .env("NO_COLOR", "1")
+    .arg("run")
+    .arg("main.ts")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  assert_eq!(output.stdout, b"Add 2 + 3 = 5\n");
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .env("NO_COLOR", "1")
+    .arg("test")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  let stdout = String::from_utf8(output.stdout).unwrap();
+  assert_contains!(stdout, "1 passed");
+}
+
+#[test]
+fn init_subcommand_with_dir_arg() {
+  let temp_dir = TempDir::new();
+  let cwd = temp_dir.path();
+  let deno_dir = util::new_deno_dir();
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .arg("init")
+    .arg("my_dir")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  let stdout = String::from_utf8(output.stdout).unwrap();
+  assert_contains!(stdout, "Project initialized");
+  assert_contains!(stdout, "cd my_dir");
+  assert_contains!(stdout, "deno run main.ts");
+  assert_contains!(stdout, "deno test");
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .env("NO_COLOR", "1")
+    .arg("run")
+    .arg("my_dir/main.ts")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  assert_eq!(output.stdout, b"Add 2 + 3 = 5\n");
+
+  let mut deno_cmd = util::deno_cmd_with_deno_dir(&deno_dir);
+  let output = deno_cmd
+    .current_dir(cwd)
+    .env("NO_COLOR", "1")
+    .arg("test")
+    .arg("my_dir/main_test.ts")
+    .stdout(Stdio::piped())
+    .spawn()
+    .unwrap()
+    .wait_with_output()
+    .unwrap();
+  assert!(output.status.success());
+  let stdout = String::from_utf8(output.stdout).unwrap();
+  assert_contains!(stdout, "1 passed");
+}