test(printenv): add some tests

tests/test_printenv.rs

@@ -0,0 +1,30 @@
+use common::util::*;
+use std::env;
+
+#[test]
+fn test_get_all() {
+    let key = "KEY";
+    env::set_var(key, "VALUE");
+    assert_eq!(env::var(key), Ok("VALUE".to_string()));
+
+    let result = TestScenario::new(util_name!()).ucmd_keepenv().run();
+    assert!(result.success);
+    assert!(result.stdout.contains("HOME="));
+    assert!(result.stdout.contains("KEY=VALUE"));
+}
+
+#[test]
+fn test_get_var() {
+    let key = "KEY";
+    env::set_var(key, "VALUE");
+    assert_eq!(env::var(key), Ok("VALUE".to_string()));
+
+    let result = TestScenario::new(util_name!())
+        .ucmd_keepenv()
+        .arg("KEY")
+        .run();
+
+    assert!(result.success);
+    assert!(!result.stdout.is_empty());
+    assert!(result.stdout.trim() == "VALUE");
+}

tests/tests.rs

@@ -77,6 +77,7 @@ generic! {
     "nl", test_nl;
     "od", test_od;
     "paste", test_paste;
+    "printenv", test_printenv;
     "printf", test_printf;
     "ptx", test_ptx;
     "pwd", test_pwd;