From ea535856b4f7715dec102655aabc57fa8dc9b015 Mon Sep 17 00:00:00 2001
From: Yonatan Goldschmidt <yon.goldschmidt@gmail.com>
Date: Sun, 5 May 2019 20:40:32 +0300
Subject: [PATCH 1/2] Raise error on out-of-range input in `chr()`

---
 vm/src/builtins.rs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/vm/src/builtins.rs b/vm/src/builtins.rs
index a82914ad1..b99a38608 100644
--- a/vm/src/builtins.rs
+++ b/vm/src/builtins.rs
@@ -73,10 +73,10 @@ fn builtin_callable(obj: PyObjectRef, vm: &VirtualMachine) -> bool {
     vm.is_callable(&obj)
 }
 
-fn builtin_chr(i: u32, _vm: &VirtualMachine) -> String {
+fn builtin_chr(i: u32, vm: &VirtualMachine) -> PyResult<String> {
     match char::from_u32(i) {
-        Some(value) => value.to_string(),
-        None => '_'.to_string(),
+        Some(value) => Ok(value.to_string()),
+        None => Err(vm.new_value_error("chr() arg not in range(0x110000)".to_string())),
     }
 }
 

From c656c5cc72b732a6200779e04d9ecb950f63a310 Mon Sep 17 00:00:00 2001
From: Yonatan Goldschmidt <yon.goldschmidt@gmail.com>
Date: Mon, 6 May 2019 03:10:53 +0300
Subject: [PATCH 2/2] Add `chr()` test snippets

---
 tests/snippets/builtin_chr.py | 8 ++++++++
 1 file changed, 8 insertions(+)
 create mode 100644 tests/snippets/builtin_chr.py

diff --git a/tests/snippets/builtin_chr.py b/tests/snippets/builtin_chr.py
new file mode 100644
index 000000000..1ad642a58
--- /dev/null
+++ b/tests/snippets/builtin_chr.py
@@ -0,0 +1,8 @@
+from testutils import assert_raises
+
+assert "a" == chr(97)
+assert "é" == chr(233)
+assert "🤡" == chr(129313)
+
+assert_raises(TypeError, lambda: chr(), "chr() takes exactly one argument (0 given)")
+assert_raises(ValueError, lambda: chr(0x110005), "ValueError: chr() arg not in range(0x110000)")