1 files changed, 54 insertions, 0 deletions
diff --git a/_test/roundtrip.py b/_test/roundtrip.py
new file mode 100644
index 0000000..446e943
--- /dev/null
+++ b/_test/roundtrip.py
@@ -0,0 +1,54 @@
+
+from __future__ import print_function
+
+"""
+helper routines for testing round trip of commented YAML data
+"""
+import textwrap
+
+import ruamel.yaml
+
+
+def dedent(data):
+    try:
+        position_of_first_newline = data.index('\n')
+        for idx in range(position_of_first_newline):
+            if not data[idx].isspace():
+                raise ValueError
+    except ValueError:
+        pass
+    else:
+        data = data[position_of_first_newline+1:]
+    return textwrap.dedent(data)
+
+
+def round_trip_load(dinp):
+    return ruamel.yaml.load(dinp, ruamel.yaml.RoundTripLoader)
+
+
+def round_trip_dump(data):
+    dumper = ruamel.yaml.RoundTripDumper
+    return ruamel.yaml.dump(data, default_flow_style=False, Dumper=dumper)
+
+
+def round_trip(inp, outp=None, extra=None, intermediate=None):
+    dinp = dedent(inp)
+    if outp is not None:
+        doutp = dedent(outp)
+    else:
+        doutp = dinp
+    if extra is not None:
+        doutp += extra
+    data = round_trip_load(dinp)
+    if intermediate is not None:
+        if isinstance(intermediate, dict):
+            for k, v in intermediate.items():
+                if data[k] != v:
+                    print('{0!r} <> {1!r}'.format(data[k], v))
+                    raise ValueError
+    res = round_trip_dump(data)
+    print('roundtrip data:\n', res, sep='')
+    assert res == doutp
+    res = round_trip_dump(data)
+    print('roundtrip second round data:\n', res, sep='')
+    assert res == doutp