test: Verify CLI

tests/cli.rs

@@ -0,0 +1,24 @@
+use assert_cmd::Command;
+
+#[test]
+fn test_stdin_success() {
+    let mut cmd = Command::cargo_bin("typos").unwrap();
+    cmd.arg("-").write_stdin("Hello world");
+    cmd.assert().success();
+}
+
+#[test]
+fn test_stdin_failure() {
+    let mut cmd = Command::cargo_bin("typos").unwrap();
+    cmd.arg("-").write_stdin("Apropriate world");
+    cmd.assert().code(2);
+}
+
+#[test]
+fn test_stdin_correct() {
+    let mut cmd = Command::cargo_bin("typos").unwrap();
+    cmd.arg("-")
+        .arg("--write-changes")
+        .write_stdin("Apropriate world");
+    cmd.assert().success().stdout("Appropriate world");
+}