Add gzip test and reread test

tests/test_lhe_writer.py

@@ -197,3 +197,41 @@ def test_write_lhe():
 </event>
 </LesHouchesEvents>"""
     )
+
+
+def test_write_lhe_twice(tmpdir):
+    file1 = tmpdir.join("test1.lhe")
+    file2 = tmpdir.join("test2.lhe")
+
+    init = pylhe.read_lhe_init(TEST_FILE_LHE_v3)
+    events = pylhe.read_lhe_with_attributes(TEST_FILE_LHE_v3)
+    # single test event
+    events = [next(events)]
+
+    # write the file
+    pylhe.write_lhe_file(init, events, filepath=file1.strpath)
+
+    # read it again
+    init = pylhe.read_lhe_init(file1)
+    events = pylhe.read_lhe_with_attributes(file1)
+
+    # write it again
+    pylhe.write_lhe_file(init, events, filepath=file2.strpath)
+
+    # assert that the files are the same
+    assert file1.read() == file2.read()
+
+
+def test_write_lhe_gzip(tmpdir):
+    file1 = tmpdir.join("test1.lhe.gz")
+
+    init = pylhe.read_lhe_init(TEST_FILE_LHE_v3)
+    events = pylhe.read_lhe_with_attributes(TEST_FILE_LHE_v3)
+    # single test event
+    events = [next(events)]
+
+    # write the file
+    pylhe.write_lhe_file(init, events, filepath=file1.strpath, gz=True)
+
+    # read it again
+    init = pylhe.read_lhe_init(file1)