Add test scenarios for the export feature (#824)

* Fix behave keyword "and" to correct case "And"
* Extract export_steps module
* Add scenario for XML export
* Add scenario for tags export
* Add scenario for fancy export
* Add scenario for yaml export
* Remove unused module export.py
* Run `make format`
* Fix `create_directory` step

features/steps/export_steps.py

@@ -0,0 +1,124 @@
+import json
+import os
+import shutil
+from xml.etree import ElementTree
+
+from behave import then, given
+
+
+@then("the output should be parsable as json")
+def check_output_json(context):
+    out = context.stdout_capture.getvalue()
+    assert json.loads(out), out
+
+
+@then('"{field}" in the json output should have {number:d} elements')
+@then('"{field}" in the json output should have 1 element')
+def check_output_field(context, field, number=1):
+    out = context.stdout_capture.getvalue()
+    out_json = json.loads(out)
+    assert field in out_json, [field, out_json]
+    assert len(out_json[field]) == number, len(out_json[field])
+
+
+@then('"{field}" in the json output should not contain "{key}"')
+def check_output_field_not_key(context, field, key):
+    out = context.stdout_capture.getvalue()
+    out_json = json.loads(out)
+    assert field in out_json
+    assert key not in out_json[field]
+
+
+@then('"{field}" in the json output should contain "{key}"')
+def check_output_field_key(context, field, key):
+    out = context.stdout_capture.getvalue()
+    out_json = json.loads(out)
+    assert field in out_json
+    assert key in out_json[field]
+
+
+@then('the json output should contain {path} = "{value}"')
+def check_json_output_path(context, path, value):
+    """ E.g.
+    the json output should contain entries.0.title = "hello"
+    """
+    out = context.stdout_capture.getvalue()
+    struct = json.loads(out)
+
+    for node in path.split("."):
+        try:
+            struct = struct[int(node)]
+        except ValueError:
+            struct = struct[node]
+    assert struct == value, struct
+
+
+@then("the output should be a valid XML string")
+def assert_valid_xml_string(context):
+    output = context.stdout_capture.getvalue()
+    xml_tree = ElementTree.fromstring(output)
+    assert xml_tree, output
+
+
+@then('"entries" node in the xml output should have {number:d} elements')
+def assert_xml_output_entries_count(context, number):
+    output = context.stdout_capture.getvalue()
+    xml_tree = ElementTree.fromstring(output)
+
+    xml_tags = (node.tag for node in xml_tree)
+    assert "entries" in xml_tags, str(list(xml_tags))
+
+    actual_entry_count = len(xml_tree.find("entries"))
+    assert actual_entry_count == number, actual_entry_count
+
+
+@then('"tags" in the xml output should contain {expected_tags_json_list}')
+def assert_xml_output_tags(context, expected_tags_json_list):
+    output = context.stdout_capture.getvalue()
+    xml_tree = ElementTree.fromstring(output)
+
+    xml_tags = (node.tag for node in xml_tree)
+    assert "tags" in xml_tags, str(list(xml_tags))
+
+    expected_tags = json.loads(expected_tags_json_list)
+    actual_tags = set(t.attrib["name"] for t in xml_tree.find("tags"))
+    assert actual_tags == set(expected_tags), [actual_tags, set(expected_tags)]
+
+
+@given('we created a directory named "{dir_name}"')
+def create_directory(context, dir_name):
+    if os.path.exists(dir_name):
+        shutil.rmtree(dir_name)
+    os.mkdir(dir_name)
+
+
+@then('"{dir_name}" should contain the files {expected_files_json_list}')
+def assert_dir_contains_files(context, dir_name, expected_files_json_list):
+    actual_files = os.listdir(dir_name)
+    expected_files = json.loads(expected_files_json_list)
+    assert actual_files == expected_files, [actual_files, expected_files]
+
+
+@then('the content of exported yaml "{file_path}" should be')
+def assert_exported_yaml_file_content(context, file_path):
+    expected_content = context.text.strip().splitlines()
+
+    with open(file_path, "r") as f:
+        actual_content = f.read().strip().splitlines()
+
+    for actual_line, expected_line in zip(actual_content, expected_content):
+        if actual_line.startswith("tags: ") and expected_line.startswith("tags: "):
+            assert_equal_tags_ignoring_order(actual_line, expected_line)
+        else:
+            assert actual_line.strip() == expected_line.strip(), [
+                actual_line.strip(),
+                expected_line.strip(),
+            ]
+
+
+def assert_equal_tags_ignoring_order(actual_line, expected_line):
+    actual_tags = set(tag.strip() for tag in actual_line[len("tags: ") :].split(","))
+    expected_tags = set(
+        tag.strip() for tag in expected_line[len("tags: ") :].split(",")
+    )
+    assert actual_tags == expected_tags, [actual_tags, expected_tags]