Better diff for contains and not-contains

Author: SimonBaeumer

CHANGELOG.md

@@ -3,6 +3,7 @@
  - Add `not-contains` assertion on `stdout` and `stderr`
  - Add validation for invalid data types in `stdout` and `stderr` assertions
  - More logging for `--verbose` option on the `test` command
+ - Add better diff format for `contains` and `not-contains` assertions on `stdout` and `stderr`
 
 # v1.0.1
 

pkg/matcher/matcher.go

@@ -81,18 +81,20 @@ func (m ContainsMatcher) Match(got interface{}, expected interface{}) MatcherRes
 		result = false
 	}
 
-	diff := difflib.UnifiedDiff{
-		A:        difflib.SplitLines(fmt.Sprintf("%s", got.(string))),
-		B:        difflib.SplitLines(fmt.Sprintf("%s", expected.(string))),
-		FromFile: "Got",
-		ToFile:   "Expected",
-		Context:  3,
-	}
-	diffText, _ := difflib.GetUnifiedDiffString(diff)
+	diff := `
+Expected
+
+%s
+
+to contain
+
+%s
+`
+	diff = fmt.Sprintf(diff, got, expected)
 
 	return MatcherResult{
 		Success: result,
-		Diff:    diffText,
+		Diff:    diff,
 	}
 }
 
@@ -132,8 +134,19 @@ func (m NotContainsMatcher) Match(got interface{}, expected interface{}) Matcher
 		result = false
 	}
 
+	diff := `
+Expected
+
+%s
+
+to not contain
+
+%s
+`
+	diff = fmt.Sprintf(diff, got, expected)
+
 	return MatcherResult{
 		Success: result,
-		Diff:    "",
+		Diff:    diff,
 	}
 }