From fbc6c02b94292a95c29a7cedb8c1f6eba9b2ad90 Mon Sep 17 00:00:00 2001
From: Adam Cooper <adam@adamcooper.sh>
Date: Sun, 31 May 2026 10:30:37 -0400
Subject: [PATCH] fix: incompatibility with rstest parametrized tests

rstest generates parametrized tests (`#[case]`) as one helper function
that is called by each test generated for the different cases. Because
of this, injectorpp's internal static counter is reused between these
test cases. The same would hold true for an injector created in any
helper function.

This patch resets the static counter to zero when the verifier is
dropped so it can be reused in these scenarios.

Additionally:
* rstest is added as a dev dependency
* An new test validates the desired behavior
---
 Cargo.toml                |  3 ++-
 src/interface/verifier.rs |  5 +++++
 tests/rstest.rs           | 24 ++++++++++++++++++++++++
 3 files changed, 31 insertions(+), 1 deletion(-)
 create mode 100644 tests/rstest.rs

diff --git a/Cargo.toml b/Cargo.toml
index 1f8f4f2..74c56b9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -26,6 +26,7 @@ http-body-util = "0.1"
 hyper-tls = "0.6"
 socket2 = "0.5.10"
 reqwest = "0.12.22"
+rstest = "0.26.1"
 
 [lints.rust]
-unexpected_cfgs = { level = "warn", check-cfg = ['cfg(coverage_nightly)'] }
\ No newline at end of file
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(coverage_nightly)'] }
diff --git a/src/interface/verifier.rs b/src/interface/verifier.rs
index f68c48c..8135c98 100644
--- a/src/interface/verifier.rs
+++ b/src/interface/verifier.rs
@@ -17,6 +17,11 @@ impl Drop for CallCountVerifier {
     fn drop(&mut self) {
         if let CallCountVerifier::WithCount { counter, expected } = self {
             let call_times = counter.load(Ordering::SeqCst);
+
+            // Because the counter is static, there's a possibility it might be reused in certain
+            // environments that don't know about injectorpp. Because of this, it is reset here.
+            counter.store(0, Ordering::SeqCst);
+
             if call_times != *expected {
                 // Avoid double panic
                 if std::thread::panicking() {
diff --git a/tests/rstest.rs b/tests/rstest.rs
new file mode 100644
index 0000000..f00372e
--- /dev/null
+++ b/tests/rstest.rs
@@ -0,0 +1,24 @@
+//! Tests that injectorpp is compatible with rstest
+
+use injectorpp::interface::injector::*;
+use rstest::rstest;
+
+fn foo(input: usize) -> usize {
+    input
+}
+
+#[rstest]
+#[case(0)]
+#[case(1)]
+fn test_multiple_cases(#[case] x: usize) {
+    let mut injector = InjectorPP::new();
+    injector
+        .when_called(injectorpp::func!(fn (foo)(usize) -> usize))
+        .will_execute(injectorpp::fake!(
+            func_type: fn(input: usize) -> usize,
+            returns: input + 1,
+            times: 1
+        ));
+
+    assert_eq!(foo(x), x + 1);
+}