From 2473c3e49f6ba539549a8bf4f87db9146044fc52 Mon Sep 17 00:00:00 2001
From: Kangzhi Shi <shikangzhi@gmail.com>
Date: Mon, 1 Feb 2021 20:25:45 +0200
Subject: [PATCH] add tests; fix OpAssert panic

---
 src/engine.rs | 15 ++++++++-------
 src/lib.rs    |  2 ++
 src/tests.rs  | 19 +++++++++++++++++++
 3 files changed, 29 insertions(+), 7 deletions(-)
 create mode 100644 src/tests.rs

diff --git a/src/engine.rs b/src/engine.rs
index 9aff2dcc91..f6a6092f9b 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -369,20 +369,18 @@ fn once<F: FnOnce(&mut StackDrive)>(f: F) -> Box<OpOnce<F>> {
     Box::new(OpOnce { f: Some(f) })
 }
 
-// F1 F2 are same identical, but workaround for closure
 struct OpTwice<F1, F2> {
     f1: Option<F1>,
     f2: Option<F2>,
 }
 impl<F1, F2> OpcodeExecutor for OpTwice<F1, F2>
 where
-    F1: FnOnce(&mut StackDrive),
+    F1: FnOnce(&mut StackDrive) -> Option<()>,
     F2: FnOnce(&mut StackDrive),
 {
     fn next(&mut self, drive: &mut StackDrive) -> Option<()> {
         if let Some(f1) = self.f1.take() {
-            f1(drive);
-            Some(())
+            f1(drive)
         } else if let Some(f2) = self.f2.take() {
             f2(drive);
             None
@@ -393,7 +391,7 @@ where
 }
 fn twice<F1, F2>(f1: F1, f2: F2) -> Box<OpTwice<F1, F2>>
 where
-    F1: FnOnce(&mut StackDrive),
+    F1: FnOnce(&mut StackDrive) -> Option<()>,
     F2: FnOnce(&mut StackDrive),
 {
     Box::new(OpTwice {
@@ -483,11 +481,12 @@ impl OpcodeDispatcher {
                     let passed = drive.ctx().string_position - drive.state.start;
                     if passed < back {
                         drive.ctx_mut().has_matched = Some(false);
-                        return;
+                        return None;
                     }
                     drive.state.string_position = drive.ctx().string_position - back;
                     drive.push_new_context(3);
                     drive.state.context_stack.last_mut().unwrap().toplevel = false;
+                    Some(())
                 },
                 |drive| {
                     let child_ctx = drive.state.popped_context.unwrap();
@@ -504,11 +503,12 @@ impl OpcodeDispatcher {
                     let passed = drive.ctx().string_position - drive.state.start;
                     if passed < back {
                         drive.skip_code(drive.peek_code(1) as usize + 1);
-                        return;
+                        return None;
                     }
                     drive.state.string_position = drive.ctx().string_position - back;
                     drive.push_new_context(3);
                     drive.state.context_stack.last_mut().unwrap().toplevel = false;
+                    Some(())
                 },
                 |drive| {
                     let child_ctx = drive.state.popped_context.unwrap();
@@ -598,6 +598,7 @@ impl OpcodeDispatcher {
                     drive.state.string_position = drive.ctx().string_position;
                     // execute UNTIL operator
                     drive.push_new_context(drive.peek_code(1) as usize + 1);
+                    Some(())
                 },
                 |drive| {
                     drive.state.repeat_stack.pop();
diff --git a/src/lib.rs b/src/lib.rs
index 4a3ed1b754..eae3be617d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,5 +1,7 @@
 pub mod constants;
 pub mod engine;
+#[cfg(test)]
+mod tests;
 
 pub const CODESIZE: usize = 4;
 
diff --git a/src/tests.rs b/src/tests.rs
new file mode 100644
index 0000000000..95922e88a7
--- /dev/null
+++ b/src/tests.rs
@@ -0,0 +1,19 @@
+use engine::{State, StrDrive};
+
+use super::*;
+
+#[test]
+fn test_2427() {
+    let str_drive = StrDrive::Str("x");
+    // r'(?<!\.)x\b'
+    let code: Vec<u32> = vec![15, 4, 0, 1, 1, 5, 5, 1, 17, 46, 1, 17, 120, 6, 10, 1];
+    let mut state = State::new(
+        str_drive,
+        0,
+        std::usize::MAX,
+        constants::SreFlag::UNICODE,
+        &code,
+    );
+    state = state.pymatch();
+    assert!(state.has_matched == Some(true));
+}