test: include a case for setting OUT_DIR

Signed-off-by: hi-rustin <rustin.liu@gmail.com>

tests/testsuite/test.rs

@@ -4897,3 +4897,51 @@ fn cargo_test_print_env_verbose() {
         )
         .run();
 }
+
+#[cargo_test]
+fn cargo_test_set_out_dir_env_var() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2021"
+            "#,
+        )
+        .file(
+            "src/lib.rs",
+            r#"
+                pub fn add(left: usize, right: usize) -> usize {
+                    left + right
+                }
+            "#,
+        )
+        .file(
+            "build.rs",
+            r#"
+                fn main() {}
+            "#,
+        )
+        .file(
+            "tests/case.rs",
+            r#"
+                #[cfg(test)]
+                pub mod tests {
+                    #[test]
+                    fn test_add() {
+                        assert!(std::env::var("OUT_DIR").is_ok());
+                        assert_eq!(foo::add(2, 5), 7);
+                    }
+                }
+            "#,
+        )
+        .build();
+
+    p.cargo("test").run();
+    p.cargo("test --package foo --test case -- tests::test_add --exact --nocapture")
+        .with_stdout_contains("test tests::test_add ... FAILED")
+        .with_status(101)
+        .run();
+}