Only use cygpath on windows if present (#586)

src/platform.rs

@@ -88,6 +88,13 @@ impl PlatformInterface for Platform {
     cygpath.current_dir(working_directory);
     cygpath.arg("--unix");
     cygpath.arg(path);
-    output(cygpath).map_err(|e| format!("Error converting shell path: {}", e))
+
+    match output(cygpath) {
+      Ok(shell_path) => Ok(shell_path),
+      Err(_) => path
+        .to_str()
+        .map(str::to_string)
+        .ok_or_else(|| String::from("Error getting current directory: unicode decode error")),
+    }
   }
 }

tests/integration.rs

@@ -2439,3 +2439,19 @@ test! {
   status: EXIT_FAILURE,
   shell: false,
 }
+
+#[cfg(windows)]
+test! {
+  name: pwsh_invocation_directory,
+  justfile: r#"
+    set shell := ["pwsh", "-NoProfile", "-c"]
+
+    pwd:
+      @Test-Path {{invocation_directory()}} > result.txt
+  "#,
+  args: (),
+  stdout: "",
+  stderr: "",
+  status: EXIT_SUCCESS,
+  shell: false,
+}