diff tool: multiline diffs supported

nested_diff/diff_tool.py

@@ -40,6 +40,7 @@ def diff(self, a, b):
         """
         return nested_diff.diff(
             a, b,
+            multiline_diff_context=self.args.text_ctx,
             A=self.args.A,
             N=self.args.N,
             O=self.args.O,
@@ -58,6 +59,15 @@ def get_argparser(self, description=None):
         parser.add_argument('file1', type=argparse.FileType())
         parser.add_argument('file2', type=argparse.FileType())
 
+        parser.add_argument(
+            '--text-ctx',
+            default=3,
+            metavar='NUM',
+            type=int,
+            help='Amount of context lines for multiline strings diffs; ' +
+                 'negative value will disable multiline diffs, default is 3'
+        )
+
         parser.add_argument(
             '--ifmt',
             type=str,

tests/cli/diff_tool/shared.multiline.a.json

@@ -0,0 +1,3 @@
+{
+   "text": "Common line,\nanother common line.\nAnd one more common line.\nStill a common line, but last, next will be different.\nFirst string for a.\nSecond striing for a.\nThird string, belongs to file a.\nAnd fourth. Again to a.\nWow! Common strings began! =)\nAnother common line.\nDifferent line. AAaaaaa!!\nAaaaa!!\nA!\n"
+}

tests/cli/diff_tool/shared.multiline.b.json

@@ -0,0 +1,3 @@
+{
+   "text": "Common line,\nanother common line.\nAnd one more common line.\nStill a common line, but last, next will be different.\nFirst string for b.\nSecond striing for b.\nThird string, belongs to file b.\nAnd fourth. Again to b.\nWow! Common strings began! =)\nAnother common line.\nDifferent line. BBbbbbb!!\nBbbbb!!\nB!\n"
+}

tests/cli/diff_tool/test_diff_tool.py

@@ -102,6 +102,53 @@ def test_ini_ifmt(capsys, expected, fullname, PY2):
         assert expected == captured.out
 
 
+def test_multiline_default(capsys, expected, fullname):
+    DiffApp(args=(
+        fullname('multiline.a.json', shared=True),
+        fullname('multiline.b.json', shared=True),
+    )).run()
+
+    captured = capsys.readouterr()
+    assert '' == captured.err
+    assert expected == captured.out
+
+
+def test_multiline_default_term(capsys, expected, fullname):
+    DiffApp(args=(
+        fullname('multiline.a.json', shared=True),
+        fullname('multiline.b.json', shared=True),
+        '--ofmt', 'term',
+    )).run()
+
+    captured = capsys.readouterr()
+    assert '' == captured.err
+    assert expected == captured.out
+
+
+def test_multiline_context_0(capsys, expected, fullname):
+    DiffApp(args=(
+        fullname('multiline.a.json', shared=True),
+        fullname('multiline.b.json', shared=True),
+        '--text-ctx', '0'
+    )).run()
+
+    captured = capsys.readouterr()
+    assert '' == captured.err
+    assert expected == captured.out
+
+
+def test_multiline_disabled(capsys, expected, fullname):
+    DiffApp(args=(
+        fullname('multiline.a.json', shared=True),
+        fullname('multiline.b.json', shared=True),
+        '--text-ctx', '-1'
+    )).run()
+
+    captured = capsys.readouterr()
+    assert '' == captured.err
+    assert expected == captured.out
+
+
 def test_text_ofmt(capsys, expected, fullname):
     DiffApp(args=(
         fullname('lists.a.json', shared=True),

tests/cli/diff_tool/test_diff_tool.test_multiline_context_0.exp

@@ -0,0 +1,17 @@
+  {'text'}
+    @@ -5,4 +5,4 @@
+-   First string for a.
+-   Second striing for a.
+-   Third string, belongs to file a.
+-   And fourth. Again to a.
++   First string for b.
++   Second striing for b.
++   Third string, belongs to file b.
++   And fourth. Again to b.
+    @@ -11,3 +11,3 @@
+-   Different line. AAaaaaa!!
+-   Aaaaa!!
+-   A!
++   Different line. BBbbbbb!!
++   Bbbbb!!
++   B!

tests/cli/diff_tool/test_diff_tool.test_multiline_default.exp

@@ -0,0 +1,22 @@
+  {'text'}
+    @@ -2,13 +2,13 @@
+    another common line.
+    And one more common line.
+    Still a common line, but last, next will be different.
+-   First string for a.
+-   Second striing for a.
+-   Third string, belongs to file a.
+-   And fourth. Again to a.
++   First string for b.
++   Second striing for b.
++   Third string, belongs to file b.
++   And fourth. Again to b.
+    Wow! Common strings began! =)
+    Another common line.
+-   Different line. AAaaaaa!!
+-   Aaaaa!!
+-   A!
++   Different line. BBbbbbb!!
++   Bbbbb!!
++   B!
+

tests/cli/diff_tool/test_diff_tool.test_multiline_default_term.exp

@@ -0,0 +1,22 @@
+  {'text'}
+    @@ -2,13 +2,13 @@
+    another common line.
+    And one more common line.
+    Still a common line, but last, next will be different.
+-   First string for a.
+-   Second striing for a.
+-   Third string, belongs to file a.
+-   And fourth. Again to a.
++   First string for b.
++   Second striing for b.
++   Third string, belongs to file b.
++   And fourth. Again to b.
+    Wow! Common strings began! =)
+    Another common line.
+-   Different line. AAaaaaa!!
+-   Aaaaa!!
+-   A!
++   Different line. BBbbbbb!!
++   Bbbbb!!
++   B!
+    

tests/cli/diff_tool/test_diff_tool.test_multiline_disabled.exp

@@ -0,0 +1,3 @@
+  {'text'}
+-   'Common line,\nanother common line.\nAnd one more common line.\nStill a common line, but last, next will be different.\nFirst string for a.\nSecond striing for a.\nThird string, belongs to file a.\nAnd fourth. Again to a.\nWow! Common strings began! =)\nAnother common line.\nDifferent line. AAaaaaa!!\nAaaaa!!\nA!\n'
++   'Common line,\nanother common line.\nAnd one more common line.\nStill a common line, but last, next will be different.\nFirst string for b.\nSecond striing for b.\nThird string, belongs to file b.\nAnd fourth. Again to b.\nWow! Common strings began! =)\nAnother common line.\nDifferent line. BBbbbbb!!\nBbbbb!!\nB!\n'