add validation error type, fix tests, add number tests

error_test.go

@@ -0,0 +1,49 @@
+package validate
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestErrorIs(t *testing.T) {
+	type TestCase struct {
+		Err    error
+		Target error
+		Is     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},
+
+		// Is specific validation error
+		{Err: ErrDisallowedChars, Target: ErrDisallowedChars, Is: true},
+		{Err: ErrMustBeGreater, Target: ErrMustBeGreater, Is: true},
+
+		// Is not specific validation error
+		{Err: Err, Target: ErrDisallowedChars},
+		{Err: Err, Target: ErrMustBeGreater},
+		{Err: ErrMustBeGreater, Target: ErrDisallowedChars},
+		{Err: ErrDisallowedChars, Target: ErrMustBeGreater},
+
+		// Is not any other error
+		{Err: ErrDisallowedChars, Target: errors.New("contains disallowed characters")},
+		{Err: ErrMustBeGreater, Target: errors.New("must be greater than %v")},
+	}
+
+	for i, tc := range testCases {
+		t.Logf("(%d) Testing %v against %v", i, tc.Err, tc.Target)
+
+		if errors.Is(tc.Err, tc.Target) {
+			if !tc.Is {
+				t.Errorf("%v should not equal %v", tc.Err, tc.Target)
+			}
+		} else {
+			if tc.Is {
+				t.Errorf("%v should equal %v", tc.Err, tc.Target)
+			}
+		}
+	}
+}