add a test which checks that vmprof is actually enabled inside greenlets; it fails on default and passes on this branch

1 files changed, 28 insertions, 0 deletions

diff --git a/extra_tests/test_vmprof_greenlet.py b/extra_tests/test_vmprof_greenlet.py
new file mode 100644
index 0000000000..7c43715ed5
--- /dev/null
+++ b/extra_tests/test_vmprof_greenlet.py
@@ -0,0 +1,28 @@
+import time
+import pytest
+import greenlet
+import vmprof
+
+def count_samples(filename):
+    stats = vmprof.read_profile(filename)
+    return len(stats.profiles)
+
+def cpuburn(duration):
+    end = time.time() + duration
+    while time.time() < end:
+        pass
+
+def test_sampling_inside_callback(tmpdir):
+    # see also test_sampling_inside_callback inside
+    # pypy/module/_continuation/test/test_stacklet.py
+    #
+    G = greenlet.greenlet(cpuburn)
+    fname = tmpdir.join('log.vmprof')
+    with fname.open('w+b') as f:
+        vmprof.enable(f.fileno(), 1/250.0)
+        G.switch(0.1)
+        vmprof.disable()
+    
+    samples = count_samples(str(fname))
+    # 0.1 seconds at 250Hz should be 25 samples
+    assert 23 < samples < 27