1 files changed, 55 insertions, 0 deletions
diff --git a/lib/error_test.go b/lib/error_test.go
new file mode 100644
index 00000000..fb2f280f
--- /dev/null
+++ b/lib/error_test.go
@@ -0,0 +1,55 @@
+package lib
+
+import (
+	"testing"
+)
+
+func TestErrorVariables(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+		want string
+	}{
+		{"ErrDuplicatedConverter", ErrDuplicatedConverter, "duplicated converter"},
+		{"ErrUnknownAction", ErrUnknownAction, "unknown action"},
+		{"ErrNotSupportedFormat", ErrNotSupportedFormat, "not supported format"},
+		{"ErrInvalidIPType", ErrInvalidIPType, "invalid IP type"},
+		{"ErrInvalidIP", ErrInvalidIP, "invalid IP address"},
+		{"ErrInvalidIPLength", ErrInvalidIPLength, "invalid IP address length"},
+		{"ErrInvalidIPNet", ErrInvalidIPNet, "invalid IPNet address"},
+		{"ErrInvalidCIDR", ErrInvalidCIDR, "invalid CIDR"},
+		{"ErrInvalidPrefix", ErrInvalidPrefix, "invalid prefix"},
+		{"ErrInvalidPrefixType", ErrInvalidPrefixType, "invalid prefix type"},
+		{"ErrCommentLine", ErrCommentLine, "comment line"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.err.Error() != tt.want {
+				t.Errorf("%s.Error() = %s, want %s", tt.name, tt.err.Error(), tt.want)
+			}
+		})
+	}
+}
+
+func TestErrorsAreNotNil(t *testing.T) {
+	errors := []error{
+		ErrDuplicatedConverter,
+		ErrUnknownAction,
+		ErrNotSupportedFormat,
+		ErrInvalidIPType,
+		ErrInvalidIP,
+		ErrInvalidIPLength,
+		ErrInvalidIPNet,
+		ErrInvalidCIDR,
+		ErrInvalidPrefix,
+		ErrInvalidPrefixType,
+		ErrCommentLine,
+	}
+
+	for _, err := range errors {
+		if err == nil {
+			t.Error("Expected error to be non-nil")
+		}
+	}
+}