ceph-volume: tests: create capture fixture for tests

Signed-off-by: Alfredo Deza <adeza@redhat.com>

src/ceph-volume/ceph_volume/tests/conftest.py

@@ -0,0 +1,16 @@
+import pytest
+
+class Capture(object):
+
+    def __init__(self, *a, **kw):
+        self.a = a
+        self.kw = kw
+        self.calls = []
+
+    def __call__(self, *a, **kw):
+        self.calls.append({'args': a, 'kwargs': kw})
+
+
+@pytest.fixture
+def capture():
+    return Capture()