diff --git a/rust-cargo-tests.el b/rust-cargo-tests.el
index 1b072ee..a029b2a 100644
--- a/rust-cargo-tests.el
+++ b/rust-cargo-tests.el
@@ -60,6 +60,22 @@
      (rust-test--wait-process-exit)
      (should (rust-test--find-string "***run interactive: 1234")))))
 
+(ert-deftest rust-test-test ()
+  (skip-unless (executable-find rust-cargo-bin))
+  (setq rust-cargo-default-arguments "")
+  (rust-test--with-main-file-buffer
+     (with-current-buffer (rust-test)
+       (rust-test--wait-process-exit)
+       (should (rust-test--find-string "running 1 test")))))
+
+(ert-deftest rust-test-test-with-arg ()
+  (skip-unless (executable-find rust-cargo-bin))
+  (setq rust-cargo-default-arguments "")
+  (rust-test--with-main-file-buffer
+     (with-current-buffer (rust-test t t)
+       (rust-test--wait-process-exit)
+       (should (rust-test--find-string "***output test")))))
+
 (ert-deftest rust-test-rustfmt ()
   (skip-unless (executable-find "rustfmt"))
   (rust-test--with-main-file-buffer
diff --git a/rust-cargo.el b/rust-cargo.el
index d323b5d..9e07fdd 100644
--- a/rust-cargo.el
+++ b/rust-cargo.el
@@ -129,10 +129,29 @@ output buffer will be in comint mode, i.e. interactive."
   (interactive "P")
   (rust--compile comint "%s run --release" rust-cargo-bin))
 
-(defun rust-test ()
-  "Test using `cargo test`"
-  (interactive)
-  (rust--compile nil "%s test %s" rust-cargo-bin rust-cargo-default-arguments))
+(defun rust-test (&optional arg is-test)
+  "Test using `cargo test`.
+
+If prefixed with `C-u`, pass additional arguments to the command
+(from a string read from the minibuffer).
+
+If optional arg IS-TEST is non-nil,
+the argument `-- --show-output' will be automatically
+added instead of being read from the minibuffer.
+
+Note that the IS-TEST arg is not meant for general use,
+and only exists for testing the `rust-mode' package. "
+  (interactive "P")
+  (let ((test-command
+         (if arg
+             (progn
+               (let ((custom-arg
+                      (if is-test
+                          "-- --show-output"
+                      (string-trim (read-string "Enter Arguments: ")))))
+                 (concat "%s test " custom-arg " %s")))
+           "%s test %s")))
+    (rust--compile nil test-command rust-cargo-bin rust-cargo-default-arguments)))
 
 (defun rust-run-clippy ()
   "Run `cargo clippy'."
diff --git a/test-project/src/main.rs b/test-project/src/main.rs
index 4d22e98..47fd06a 100644
--- a/test-project/src/main.rs
+++ b/test-project/src/main.rs
@@ -23,3 +23,11 @@ fn main() {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn test() {
+        println!("***output test");
+    }
+}