improve validate testing with examples

also simplified structure of test cases and failure logging

error_test.go

@@ -2,48 +2,48 @@ package validate
 
 import (
 	"errors"
+	"fmt"
 	"testing"
 )
 
 func TestErrorIs(t *testing.T) {
 	type TestCase struct {
-		Err    error
-		Target error
-		Is     bool
+		A    error
+		B    error
+		Want bool
 	}
 
 	testCases := []TestCase{
-		// Is any validation error
-		{Err: Err, Target: Err, Is: true},
-		{Err: ErrDisallowedChars, Target: Err, Is: true},
-		{Err: ErrMustBeGreater, Target: Err, Is: true},
+		// Want any validation error
+		{A: Err, B: Err, Want: true},
+		{A: ErrDisallowedChars, B: Err, Want: true},
+		{A: ErrMustBeGreater, B: Err, Want: true},
 
-		// Is specific validation error
-		{Err: ErrDisallowedChars, Target: ErrDisallowedChars, Is: true},
-		{Err: ErrMustBeGreater, Target: ErrMustBeGreater, Is: true},
+		// Want specific validation error
+		{A: ErrDisallowedChars, B: ErrDisallowedChars, Want: true},
+		{A: ErrMustBeGreater, B: ErrMustBeGreater, Want: true},
 
-		// Is not specific validation error
-		{Err: Err, Target: ErrDisallowedChars},
-		{Err: Err, Target: ErrMustBeGreater},
-		{Err: ErrMustBeGreater, Target: ErrDisallowedChars},
-		{Err: ErrDisallowedChars, Target: ErrMustBeGreater},
+		// Want not specific validation error
+		{A: Err, B: ErrDisallowedChars},
+		{A: Err, B: ErrMustBeGreater},
+		{A: ErrMustBeGreater, B: ErrDisallowedChars},
+		{A: ErrDisallowedChars, B: ErrMustBeGreater},
 
-		// Is not any other error
-		{Err: ErrDisallowedChars, Target: errors.New("contains disallowed characters")},
-		{Err: ErrMustBeGreater, Target: errors.New("must be greater than %v")},
+		// Want not any other error
+		{A: ErrDisallowedChars, B: errors.New("contains disallowed characters")},
+		{A: ErrMustBeGreater, B: errors.New("must be greater than %v")},
 	}
 
-	for i, tc := range testCases {
-		t.Logf("(%d) Testing %v against %v", i, tc.Err, tc.Target)
+	for _, testCase := range testCases {
+		a, b, want := testCase.A, testCase.B, testCase.Want
 
-		if errors.Is(tc.Err, tc.Target) {
-			if !tc.Is {
-				t.Errorf("%v should not equal %v", tc.Err, tc.Target)
+		t.Run(fmt.Sprintf("%v/%v", a, b), func(t *testing.T) {
+			got := errors.Is(a, b)
+
+			if got != want {
+				t.Error("got", got)
+				t.Error("want", want)
 			}
-		} else {
-			if tc.Is {
-				t.Errorf("%v should equal %v", tc.Err, tc.Target)
-			}
-		}
+		})
 	}
 }