add tests

dnserror_test.go

@@ -0,0 +1,42 @@
+// TINYGO test for DNSError.
+
+package net
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestDNSErrorError(t *testing.T) {
+	tests := []struct {
+		name string
+		e    *DNSError
+		want string
+	}{
+		{"nil", nil, "<nil>"},
+		{"no server", &DNSError{Err: "no such host", Name: "example.com"},
+			"lookup example.com: no such host"},
+		{"with server", &DNSError{Err: "timeout", Name: "example.com", Server: "8.8.8.8:53"},
+			"lookup example.com on 8.8.8.8:53: timeout"},
+	}
+	for _, tt := range tests {
+		if got := tt.e.Error(); got != tt.want {
+			t.Errorf("%s: Error() = %q, want %q", tt.name, got, tt.want)
+		}
+	}
+}
+
+func TestDNSErrorUnwrap(t *testing.T) {
+	inner := errors.New("boom")
+	e := &DNSError{Err: "x", UnwrapErr: inner}
+	if got := e.Unwrap(); got != inner {
+		t.Errorf("Unwrap() = %v, want %v", got, inner)
+	}
+	if !errors.Is(e, inner) {
+		t.Errorf("errors.Is(e, inner) = false, want true")
+	}
+
+	if (&DNSError{Err: "x"}).Unwrap() != nil {
+		t.Errorf("Unwrap() with no UnwrapErr should be nil")
+	}
+}