RustPython
diff --git a/‎Lib/test/test_time.py
Copy file name to clipboardExpand all lines: Lib/test/test_time.py
+2-1Lines changed: 2 additions & 1 deletion b/‎Lib/test/test_time.py
Copy file name to clipboardExpand all lines: Lib/test/test_time.py
+2-1Lines changed: 2 additions & 1 deletion
diff --git a/‎extra_tests/snippets/stdlib_datetime.py
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+5Lines changed: 5 additions & 0 deletions b/‎extra_tests/snippets/stdlib_datetime.py
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+5Lines changed: 5 additions & 0 deletions
diff --git a/‎vm/src/stdlib/time.rs
Copy file name to clipboardExpand all lines: vm/src/stdlib/time.rs
+11-1Lines changed: 11 additions & 1 deletion b/‎vm/src/stdlib/time.rs
Copy file name to clipboardExpand all lines: vm/src/stdlib/time.rs
+11-1Lines changed: 11 additions & 1 deletion
@@ -157,7 +157,8 @@ def test_sleep(self):
         self.assertRaises(ValueError, time.sleep, -1)
         time.sleep(1.2)
 
-    @unittest.skip("TODO: RUSTPYTHON, thread 'main' panicked at 'a Display implementation returned an error unexpectedly: Error'")
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
     def test_strftime(self):
         tt = time.gmtime(self.t)
         for directive in ('a', 'A', 'b', 'B', 'c', 'd', 'H', 'I',
 
@@ -131,6 +131,11 @@ def __init__(self, offset, name):
 assert_raises(NotImplementedError, ne.utcoffset, dt)
 assert_raises(NotImplementedError, ne.dst, dt)
 
+# unsupport format in strptime returns arg itself
+# in linux. Todo: add cases for Mac/Windows
+if sys.platform.startswith("linux"):
+    assert_equal(_time.strftime("%?"), "%?")
+
 # XXX: bug #1302
 # def test_normal(self):
 #fo = FixedOffset(3, "Three")
 
@@ -207,8 +207,18 @@ mod time {
 
     #[pyfunction]
     fn strftime(format: PyStrRef, t: OptionalArg<PyStructTime>, vm: &VirtualMachine) -> PyResult {
+        use std::fmt::Write;
+
         let instant = t.naive_or_local(vm)?;
-        let formatted_time = instant.format(format.as_str()).to_string();
+        let mut formatted_time = String::new();
+
+        /*
+         * chrono doesn't support all formats and it
+         * raises an error if unsupported format is supplied.
+         * If error happens, we set result as input arg.
+         */
+        write!(&mut formatted_time, "{}", instant.format(format.as_str()))
+            .unwrap_or_else(|_| formatted_time = format.to_string());
         Ok(vm.ctx.new_str(formatted_time).into())
     }