handle case with long lines in comparators

Author: hjwp

pytest_icdiff.py

@@ -1,3 +1,4 @@
+# pylint: disable=inconsistent-return-statements
 from pprintpp import pformat
 import icdiff
 
@@ -22,7 +23,8 @@ def pytest_assertrepr_compare(config, op, left, right):
         shortest_right = pformat(right, indent=2, width=1).splitlines()
         cols = max(len(l) for l in shortest_left + shortest_right) * 2
     else:
-        cols = max(len(l) for l in wide_left + wide_right) * 2
+        longest_line_length = max(len(l) for l in wide_left + wide_right)
+        cols = int(min(longest_line_length, cols / 2))
 
     pretty_left = pformat(left, indent=2, width=cols / 2).splitlines()
     pretty_right = pformat(right, indent=2, width=cols / 2).splitlines()

tests/test_pytest_icdiff.py

@@ -188,3 +188,17 @@ def test_a():
     output = testdir.runpytest().stdout.str()
     drilldown_expression = 'where 3 = len([1, 2, 3])'
     assert drilldown_expression in output
+
+
+def test_long_lines_in_comparators_are_wrapped_sensibly(testdir):
+    left = {1: "hello " * 20}
+    right = {1: "hella " * 20}
+    testdir.makepyfile(
+        f"""
+        def test_one():
+            assert {left!r} == {right!r}
+        """
+    )
+    output = testdir.runpytest('-vv', '--color=yes').stdout.str()
+    comparison_line = next(l for l in output.splitlines() if '1:' in l and "assert" not in l)
+    assert len(comparison_line) < 120