+ Extended Assertions#mu_pp to encoding validity output for strings t…

…o improve diffs.

+ Extended Assertions#mu_pp to output encoding and validity if invalid to improve diffs.
+ Extended Assertions#mu_pp_for_diff to make escaped newlines more obvious in diffs.

[git-p4: depot-paths = "//src/minitest/dev/": change = 11903]

lib/minitest/assertions.rb

@@ -101,31 +101,39 @@ def diff exp, act
 
     ##
     # This returns a human-readable version of +obj+. By default
-    # #inspect is called. You can override this to use #pretty_print
+    # #inspect is called. You can override this to use #pretty_inspect
     # if you want.
+    #
+    # See Minitest::Test.make_my_diffs_pretty!
 
     def mu_pp obj
       s = obj.inspect
 
       if defined? Encoding then
         s = s.encode Encoding.default_external
 
-        if String === obj && obj.encoding != Encoding.default_external then
-          s = "# encoding: #{obj.encoding}\n#{s}"
+        if String === obj && (obj.encoding != Encoding.default_external ||
+                              !obj.valid_encoding?) then
+          enc = "# encoding: #{obj.encoding}"
+          val = "#    valid: #{obj.valid_encoding?}"
+          s = "#{enc}\n#{val}\n#{s}"
         end
       end
 
       s
     end
 
     ##
-    # This returns a diff-able human-readable version of +obj+. This
-    # differs from the regular mu_pp because it expands escaped
+    # This returns a diff-able more human-readable version of +obj+.
+    # This differs from the regular mu_pp because it expands escaped
     # newlines and makes hex-values generic (like object_ids). This
     # uses mu_pp to do the first pass and then cleans it up.
 
     def mu_pp_for_diff obj
-      mu_pp(obj).gsub(/\\n/, "\n").gsub(/:0x[a-fA-F0-9]{4,}/m, ":0xXXXXXX")
+      mu_pp(obj).
+        gsub(/\\n/, "\n").     # escaped newlines      -> newlines
+        gsub(/\\\n/, "\\n\n"). # escaped slash+newline -> escaped newline+newline
+        gsub(/:0x[a-fA-F0-9]{4,}/m, ":0xXXXXXX") # anonymize hex values
     end
 
     ##

test/minitest/test_minitest_test.rb

@@ -915,8 +915,11 @@ def test_assert_equal_string_encodings
     msg = <<-EOM.gsub(/^ {10}/, "")
           --- expected
           +++ actual
-          @@ -1 +1,2 @@
+          @@ -1,3 +1,3 @@
+          -# encoding: UTF-8
+          -#    valid: false
           +# encoding: ASCII-8BIT
+          +#    valid: true
            "bad-utf8-\\xF1.txt"
           EOM
 
@@ -931,9 +934,11 @@ def test_assert_equal_string_encodings_both_different
     msg = <<-EOM.gsub(/^ {10}/, "")
           --- expected
           +++ actual
-          @@ -1,2 +1,2 @@
+          @@ -1,3 +1,3 @@
           -# encoding: US-ASCII
+          -#    valid: false
           +# encoding: ASCII-8BIT
+          +#    valid: true
            "bad-utf8-\\xF1.txt"
           EOM
 
@@ -1055,6 +1060,60 @@ def test_assert_equal_different_short_multiline
     end
   end
 
+  def test_assert_equal_unescape_newlines
+    msg = <<-'EOM'.gsub(/^ {10}/, "") # NOTE single quotes on heredoc
+          --- expected
+          +++ actual
+          @@ -1,2 +1,2 @@
+          -"hello
+          +"hello\n
+           world"
+          EOM
+
+    assert_triggered msg do
+      act = 'hello\nworld'
+      exp = "hello\nworld"
+
+      @tc.assert_equal exp, act
+    end
+  end
+
+  def assert_mu_pp exp, input
+    @tc.assert_equal exp, mu_pp(input)
+  end
+
+  def test_mu_pp
+    @assertion_count += 4
+
+    assert_mu_pp 42.inspect,    42
+    assert_mu_pp %w[a b c].inspect,    %w[a b c]
+    assert_mu_pp "\"hello world\"",    "hello world"
+    assert_mu_pp "\"hello\\nworld\"",   "hello\nworld"
+    assert_mu_pp "\"hello\\\\nworld\"", 'hello\nworld' # notice single quotes
+  end
+
+  def assert_mu_pp_for_diff exp, input
+    @tc.assert_equal exp, mu_pp_for_diff(input)
+  end
+
+  def test_mu_pp_for_diff
+    @assertion_count += 3
+
+    assert_mu_pp_for_diff "#<Object:0xXXXXXX>", Object.new
+    assert_mu_pp_for_diff "\"hello world\"",    "hello world"
+    assert_mu_pp_for_diff "\"hello\nworld\"",   "hello\nworld"
+
+    exp = "# encoding: ASCII-8BIT\n#    valid: true\n\"hello\nworld\""
+    assert_mu_pp_for_diff exp, "hello\nworld".b
+  end
+
+  def test_mu_pp_for_diff_single_quotes_counter
+    @assertion_count += 1
+
+    assert_mu_pp_for_diff "\"hello\\n\nworld\"", 'hello\nworld'
+    assert_mu_pp_for_diff "\"hello\nworld\"",    "hello\nworld"
+  end
+
   def test_assert_equal_does_not_allow_lhs_nil
     if Minitest::VERSION =~ /^6/ then
       warn "Time to strip the MT5 test"