tests ~ fix WSL testing

+ ToDO added ~ when possible, test under WSL2 and differentiate/liberalize if possible

tests/common/util.rs

@@ -31,6 +31,22 @@ static ALREADY_RUN: &'static str =
      testing();";
 static MULTIPLE_STDIN_MEANINGLESS: &'static str = "Ucommand is designed around a typical use case of: provide args and input stream -> spawn process -> block until completion -> return output streams. For verifying that a particular section of the input stream is what causes a particular behavior, use the Command type directly.";
 
+/// Test if the program is running under WSL
+// ref: <https://github.com/microsoft/WSL/issues/4555> @@ <https://archive.is/dP0bz>
+// ToDO: test on WSL2 which likely doesn't need special handling; plan change to `is_wsl_1()` if WSL2 is less needy
+pub fn is_wsl() -> bool {
+    #[cfg(target_os = "linux")]
+    {
+    if let Ok(b) = std::fs::read("/proc/sys/kernel/osrelease") {
+        if let Ok(s) = std::str::from_utf8(&b) {
+            let a = s.to_ascii_lowercase();
+            return a.contains("microsoft") || a.contains("wsl");
+        }
+    }
+    }
+    false
+}
+
 fn read_scenario_fixture<S: AsRef<OsStr>>(tmpd: &Option<Rc<TempDir>>, file_rel_path: S) -> String {
     let tmpdir_path = tmpd.as_ref().unwrap().as_ref().path();
     AtPath::new(tmpdir_path).read(file_rel_path.as_ref().to_str().unwrap())

tests/test_chgrp.rs

@@ -98,7 +98,10 @@ fn test_preserve_root_symlink() {
 #[test]
 #[cfg(target_os = "linux")]
 fn test_reference() {
-    if get_effective_gid() != 0 {
+    // skip for root or MS-WSL
+    // * MS-WSL is bugged (as of 2019-12-25), allowing non-root accounts su-level privileges for `chgrp`
+    // * for MS-WSL, succeeds and stdout == 'group of /etc retained as root'
+    if !(get_effective_gid() == 0 || is_wsl()) {
         new_ucmd!()
             .arg("-v")
             .arg("--reference=/etc/passwd")

tests/test_du.rs

@@ -47,7 +47,12 @@ fn _du_basics_subdir(s: String) {
 }
 #[cfg(not(target_os = "macos"))]
 fn _du_basics_subdir(s: String) {
-    assert_eq!(s, "8\tsubdir/deeper\n");
+    // MS-WSL linux has altered expected output
+    if !is_wsl() {
+        assert_eq!(s, "8\tsubdir/deeper\n");
+    } else {
+        assert_eq!(s, "0\tsubdir/deeper\n");
+    }
 }
 
 #[test]
@@ -81,7 +86,12 @@ fn _du_soft_link(s: String) {
 }
 #[cfg(not(target_os = "macos"))]
 fn _du_soft_link(s: String) {
-    assert_eq!(s, "16\tsubdir/links\n");
+    // MS-WSL linux has altered expected output
+    if !is_wsl() {
+        assert_eq!(s, "16\tsubdir/links\n");
+    } else {
+        assert_eq!(s, "8\tsubdir/links\n");
+    }
 }
 
 #[test]
@@ -104,7 +114,12 @@ fn _du_hard_link(s: String) {
 }
 #[cfg(not(target_os = "macos"))]
 fn _du_hard_link(s: String) {
-    assert_eq!(s, "16\tsubdir/links\n");
+    // MS-WSL linux has altered expected output
+    if !is_wsl() {
+        assert_eq!(s, "16\tsubdir/links\n");
+    } else {
+        assert_eq!(s, "8\tsubdir/links\n");
+    }
 }
 
 #[test]
@@ -123,5 +138,10 @@ fn _du_d_flag(s: String) {
 }
 #[cfg(not(target_os = "macos"))]
 fn _du_d_flag(s: String) {
-    assert_eq!(s, "28\t./subdir\n36\t./\n");
+    // MS-WSL linux has altered expected output
+    if !is_wsl() {
+        assert_eq!(s, "28\t./subdir\n36\t./\n");
+    } else {
+        assert_eq!(s, "8\t./subdir\n8\t./\n");
+    }
 }