fix: remove duplicate test declarations from PR #12/#13 conflict

Phase 4.2 (PR #12) and test coverage improvement (PR #13) independently
added overlapping test functions. Remove duplicates from PR #13 files:

- internal/dns/iterative_test.go: remove TestExtractNSNames,
  TestExtractNSNamesEmpty, TestIterativeQueryWithExchangeSuccess,
  TestIterativeQueryWithExchangeNilResponse, TestIterativeQueryWithExchangeTCPFallback
  (kept in roots_test.go and query_test.go from PR #12)
- internal/output/coverage_test.go: remove TestRRDataStringDefault,
  TestContainsString, TestCollectUniqueServerIPs, TestNewFormatterNilWriter
  (kept in stats_test.go and formatter_test.go from PR #12)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: multica-agent <github@multica.ai>

internal/dns/iterative_test.go

@@ -10,38 +10,6 @@ import (
 	"github.com/miekg/dns"
 )
 
-func TestIterativeQueryWithExchangeSuccess(t *testing.T) {
-	resp := new(dns.Msg)
-	resp.SetReply(new(dns.Msg))
-	resp.RecursionDesired = false
-	resp.Answer = append(resp.Answer, &dns.A{
-		Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 300},
-		A:   net.ParseIP("93.184.216.34"),
-	})
-
-	exchangeFn := func(ctx context.Context, server string, msg *dns.Msg, useTCP bool) (*dns.Msg, error) {
-		if msg.RecursionDesired {
-			t.Error("iterative query should have RecursionDesired=false")
-		}
-		return resp.Copy(), nil
-	}
-
-	cfg := &QueryConfig{
-		UDPSize: 2048,
-		Retries: 1,
-		UseTCP:  false,
-	}
-
-	server := net.ParseIP("8.8.8.8")
-	result, err := IterativeQueryWithExchange(context.Background(), server, "example.com", TypeA, cfg, exchangeFn)
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if len(result.Answer) != 1 {
-		t.Fatalf("expected 1 answer, got %d", len(result.Answer))
-	}
-}
-
 func TestIterativeQueryWithExchangeNilConfig(t *testing.T) {
 	resp := new(dns.Msg)
 	resp.SetReply(new(dns.Msg))
@@ -57,76 +25,6 @@ func TestIterativeQueryWithExchangeNilConfig(t *testing.T) {
 	}
 }
 
-func TestIterativeQueryWithExchangeNilResponse(t *testing.T) {
-	var mu sync.Mutex
-	callCount := 0
-	exchangeFn := func(ctx context.Context, server string, msg *dns.Msg, useTCP bool) (*dns.Msg, error) {
-		mu.Lock()
-		callCount++
-		mu.Unlock()
-		return nil, nil
-	}
-
-	cfg := &QueryConfig{
-		UDPSize: 2048,
-		Retries: 2,
-		UseTCP:  false,
-	}
-
-	server := net.ParseIP("8.8.8.8")
-	_, err := IterativeQueryWithExchange(context.Background(), server, "example.com", TypeA, cfg, exchangeFn)
-	if err == nil {
-		t.Fatal("expected error when response is nil")
-	}
-	if callCount != 2 {
-		t.Errorf("expected 2 attempts, got %d", callCount)
-	}
-}
-
-func TestIterativeQueryWithExchangeTCPFallback(t *testing.T) {
-	truncated := new(dns.Msg)
-	truncated.Truncated = true
-	truncated.SetReply(new(dns.Msg))
-
-	full := new(dns.Msg)
-	full.SetReply(new(dns.Msg))
-	full.Answer = append(full.Answer, &dns.A{
-		Hdr: dns.RR_Header{Name: "example.com.", Rrtype: dns.TypeA},
-		A:   net.ParseIP("1.2.3.4"),
-	})
-
-	var mu sync.Mutex
-	calls := []bool{}
-	exchangeFn := func(ctx context.Context, server string, msg *dns.Msg, useTCP bool) (*dns.Msg, error) {
-		mu.Lock()
-		calls = append(calls, useTCP)
-		mu.Unlock()
-		if !useTCP {
-			return truncated.Copy(), nil
-		}
-		return full.Copy(), nil
-	}
-
-	cfg := &QueryConfig{
-		UDPSize:  2048,
-		Retries:  1,
-		UseTCP:   false,
-		AllowTCP: true,
-	}
-
-	server := net.ParseIP("8.8.8.8")
-	result, err := IterativeQueryWithExchange(context.Background(), server, "example.com", TypeA, cfg, exchangeFn)
-	if err != nil {
-		t.Fatalf("unexpected error: %v", err)
-	}
-	if len(calls) != 2 {
-		t.Errorf("expected 2 calls (UDP + TCP), got %d", len(calls))
-	}
-	if len(result.Answer) != 1 {
-		t.Fatalf("expected 1 answer, got %d", len(result.Answer))
-	}
-}
-
 func TestIterativeQueryWithExchangeAlwaysTCP(t *testing.T) {
 	resp := new(dns.Msg)
 	resp.SetReply(new(dns.Msg))
@@ -203,24 +101,6 @@ func TestIterativeQueryWithExchangeContextCancel(t *testing.T) {
 	}
 }
 
-func TestExtractNSNames(t *testing.T) {
-	rrs := []dns.RR{
-		&dns.NS{Hdr: dns.RR_Header{Name: ".", Rrtype: dns.TypeNS}, Ns: "a.root-servers.net."},
-		&dns.NS{Hdr: dns.RR_Header{Name: ".", Rrtype: dns.TypeNS}, Ns: "b.root-servers.net."},
-	}
-	names := extractNSNames(rrs)
-	if len(names) != 2 {
-		t.Fatalf("expected 2 names, got %d", len(names))
-	}
-}
-
-func TestExtractNSNamesEmpty(t *testing.T) {
-	names := extractNSNames(nil)
-	if len(names) != 0 {
-		t.Errorf("expected 0 names, got %d", len(names))
-	}
-}
-
 func TestIterativeQueryWithExchangeZeroUDPSize(t *testing.T) {
 	resp := new(dns.Msg)
 	resp.SetReply(new(dns.Msg))

internal/output/coverage_test.go

@@ -52,18 +52,6 @@ func TestRRDataString(t *testing.T) {
 	}
 }
 
-func TestRRDataStringDefault(t *testing.T) {
-	soa := &miekgdns.SOA{
-		Hdr:  miekgdns.RR_Header{Name: "example.com.", Rrtype: miekgdns.TypeSOA, Class: miekgdns.ClassINET, Ttl: 3600},
-		Ns:   "ns1.example.com.",
-		Mbox: "admin.example.com.",
-	}
-	got := rrDataString(soa)
-	if got == "" {
-		t.Error("expected non-empty string for SOA default case")
-	}
-}
-
 func TestSummaryTypeLabel(t *testing.T) {
 	cases := []struct {
 		input string
@@ -87,22 +75,6 @@ func TestSummaryTypeLabel(t *testing.T) {
 	}
 }
 
-func TestContainsString(t *testing.T) {
-	items := []string{"a", "b", "c"}
-	if !containsString(items, "a") {
-		t.Error("containsString should find 'a'")
-	}
-	if !containsString(items, "c") {
-		t.Error("containsString should find 'c'")
-	}
-	if containsString(items, "d") {
-		t.Error("containsString should not find 'd'")
-	}
-	if containsString(nil, "a") {
-		t.Error("containsString on nil should return false")
-	}
-}
-
 func TestCollectServers(t *testing.T) {
 	ref := traverse.NewReferral("example.com.", dns.TypeA, "com.", 1, 0.5, nil)
 	resp := &traverse.Response{
@@ -848,20 +820,6 @@ func TestJSONFormatterWriteProgressShowProgressFalse(t *testing.T) {
 
 // ---- runner.go coverage ----
 
-func TestCollectUniqueServerIPs(t *testing.T) {
-	ref := traverse.NewReferral("example.com.", dns.TypeA, ".", 0, 1.0, nil)
-	results := []traverse.TraversalResult{
-		{Referral: ref, Response: &traverse.Response{Server: net.ParseIP("1.2.3.4"), Referral: ref, Type: traverse.RespAnswer}},
-		{Referral: ref, Response: &traverse.Response{Server: net.ParseIP("1.2.3.4"), Referral: ref, Type: traverse.RespAnswer}}, // duplicate
-		{Referral: ref, Response: &traverse.Response{Server: net.ParseIP("5.6.7.8"), Referral: ref, Type: traverse.RespAnswer}},
-		{Referral: ref, Response: nil},
-	}
-	ips := collectUniqueServerIPs(results)
-	if len(ips) != 2 {
-		t.Errorf("expected 2 unique IPs, got %d", len(ips))
-	}
-}
-
 func TestRunTraversalNilTraverser(t *testing.T) {
 	_, err := RunTraversal(context.Background(), nil, nil, nil, "example.com")
 	if err == nil {
@@ -876,13 +834,6 @@ func TestNewFormatterNilConfig(t *testing.T) {
 	}
 }
 
-func TestNewFormatterNilWriter(t *testing.T) {
-	f := NewFormatter(DefaultConfig(), nil)
-	if f == nil {
-		t.Fatal("NewFormatter with nil writer should not return nil")
-	}
-}
-
 func TestAttachHooksNilCfg(t *testing.T) {
 	h := AttachHooks(nil, nil)
 	if h != nil {