From 0c24e2e2f78aef0353a417b6e829d45902b84461 Mon Sep 17 00:00:00 2001
From: Richard Dymond <rjdymond@gmail.com>
Date: Fri, 8 Mar 2024 17:24:51 -0400
Subject: [PATCH] Fix how the --stop option of rzxplay.py handles empty frames

---
 skoolkit/rzxplay.py   |  4 ++--
 tests/test_rzxplay.py | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/skoolkit/rzxplay.py b/skoolkit/rzxplay.py
index f7844e38..59846c6d 100644
--- a/skoolkit/rzxplay.py
+++ b/skoolkit/rzxplay.py
@@ -337,7 +337,7 @@ def process_block(block, options, context):
     prev_scr = [None] * 6912
     show_progress = not options.quiet
     fps = options.fps
-    stop = options.stop
+    stop = options.stop or total_frames
     exec_map = context.exec_map
     tracefile = context.tracefile
     if tracefile:
@@ -394,7 +394,7 @@ def process_block(block, options, context):
         if show_progress:
             p = (context.frame_count / total_frames) * 100
             write(f'[{p:5.1f}%]\x08\x08\x08\x08\x08\x08\x08\x08')
-        if context.frame_count == stop:
+        if context.frame_count >= stop:
             context.stop = True
             break
 
diff --git a/tests/test_rzxplay.py b/tests/test_rzxplay.py
index bc35f623..2d65e756 100644
--- a/tests/test_rzxplay.py
+++ b/tests/test_rzxplay.py
@@ -1215,6 +1215,26 @@ def test_option_stop(self):
         """
         self._test_rzx(rzx, exp_output, '--stop 2 --quiet --no-screen', exp_trace)
 
+    def test_option_stop_with_empty_frame(self):
+        ram = [0] * 0xC000
+        pc = 0xE000
+        code = (
+            0xAF, # XOR A
+            0xA8, # XOR B
+            0xA9, # XOR C
+        )
+        ram[pc - 0x4000:pc - 0x4000 + len(code)] = code
+        registers = {'PC': pc}
+        z80data = self.write_z80_file(None, ram, registers=registers, ret_data=True)
+        rzx = RZX()
+        frames = [(1, 0, []), (0, 0, []), (2, 0, [])]
+        rzx.add_snapshot(z80data, 'z80', frames)
+        exp_output = ''
+        exp_trace = """
+            F:0 C:00001 I:00000 $E000 XOR A
+        """
+        self._test_rzx(rzx, exp_output, '--stop 1 --quiet --no-screen', exp_trace)
+
     def test_option_V(self):
         for option in ('-V', '--version'):
             output, error = self.run_rzxplay(option, catch_exit=0)