Add unit tests for extractHostAndPort utility function

27 test cases covering URL/host:port parsing for node configuration:
- Scheme stripping (http://, https://)
- Path removal from URLs
- IPv4 addresses with and without ports
- IPv6 addresses (bracketed with port, unbracketed)
- Edge cases (empty string, localhost, port-only)
- Error cases (malformed brackets)

Documents current behavior: bracketed IPv6 without port returns error
(net.SplitHostPort limitation).

internal/api/config_handlers_host_test.go

@@ -2,6 +2,207 @@ package api
 
 import "testing"
 
+func TestExtractHostAndPort(t *testing.T) {
+	tests := []struct {
+		name     string
+		hostStr  string
+		wantHost string
+		wantPort string
+		wantErr  bool
+	}{
+		// Basic host:port
+		{
+			name:     "simple host with port",
+			hostStr:  "example.com:8006",
+			wantHost: "example.com",
+			wantPort: "8006",
+		},
+		{
+			name:     "host without port",
+			hostStr:  "example.com",
+			wantHost: "example.com",
+			wantPort: "",
+		},
+
+		// HTTP/HTTPS scheme stripping
+		{
+			name:     "https scheme stripped",
+			hostStr:  "https://example.com:8006",
+			wantHost: "example.com",
+			wantPort: "8006",
+		},
+		{
+			name:     "http scheme stripped",
+			hostStr:  "http://example.com:8006",
+			wantHost: "example.com",
+			wantPort: "8006",
+		},
+		{
+			name:     "https scheme without port",
+			hostStr:  "https://example.com",
+			wantHost: "example.com",
+			wantPort: "",
+		},
+		{
+			name:     "http scheme without port",
+			hostStr:  "http://example.com",
+			wantHost: "example.com",
+			wantPort: "",
+		},
+
+		// Path stripping
+		{
+			name:     "path stripped from host:port",
+			hostStr:  "example.com:8006/api/v1",
+			wantHost: "example.com",
+			wantPort: "8006",
+		},
+		{
+			name:     "path stripped from host without port",
+			hostStr:  "example.com/api/v1",
+			wantHost: "example.com",
+			wantPort: "",
+		},
+		{
+			name:     "full URL with scheme path and port",
+			hostStr:  "https://example.com:8443/some/path",
+			wantHost: "example.com",
+			wantPort: "8443",
+		},
+		{
+			name:     "trailing slash stripped",
+			hostStr:  "example.com/",
+			wantHost: "example.com",
+			wantPort: "",
+		},
+
+		// IPv4 addresses
+		{
+			name:     "IPv4 with port",
+			hostStr:  "192.168.1.100:8006",
+			wantHost: "192.168.1.100",
+			wantPort: "8006",
+		},
+		{
+			name:     "IPv4 without port",
+			hostStr:  "192.168.1.100",
+			wantHost: "192.168.1.100",
+			wantPort: "",
+		},
+		{
+			name:     "IPv4 with scheme and port",
+			hostStr:  "https://192.168.1.100:8006",
+			wantHost: "192.168.1.100",
+			wantPort: "8006",
+		},
+
+		// IPv6 addresses with brackets
+		{
+			name:     "IPv6 with brackets and port",
+			hostStr:  "[2001:db8::1]:8006",
+			wantHost: "2001:db8::1",
+			wantPort: "8006",
+		},
+		{
+			name:     "IPv6 with brackets no port returns error",
+			hostStr:  "[2001:db8::1]",
+			wantErr:  true, // net.SplitHostPort fails on bracketed IPv6 without port
+		},
+		{
+			name:     "IPv6 with scheme brackets and port",
+			hostStr:  "https://[2001:db8::1]:8006",
+			wantHost: "2001:db8::1",
+			wantPort: "8006",
+		},
+		{
+			name:     "IPv6 loopback with brackets",
+			hostStr:  "[::1]:8006",
+			wantHost: "::1",
+			wantPort: "8006",
+		},
+
+		// IPv6 without brackets (no port case)
+		{
+			name:     "IPv6 without brackets returns as-is",
+			hostStr:  "2001:db8::1",
+			wantHost: "2001:db8::1",
+			wantPort: "",
+		},
+		{
+			name:     "IPv6 full address without brackets",
+			hostStr:  "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+			wantHost: "2001:0db8:85a3:0000:0000:8a2e:0370:7334",
+			wantPort: "",
+		},
+		{
+			name:     "IPv6 loopback without brackets",
+			hostStr:  "::1",
+			wantHost: "::1",
+			wantPort: "",
+		},
+
+		// Edge cases
+		{
+			name:     "empty string",
+			hostStr:  "",
+			wantHost: "",
+			wantPort: "",
+		},
+		{
+			name:     "only port colon",
+			hostStr:  ":8006",
+			wantHost: "",
+			wantPort: "8006",
+		},
+		{
+			name:     "localhost with port",
+			hostStr:  "localhost:8006",
+			wantHost: "localhost",
+			wantPort: "8006",
+		},
+		{
+			name:     "localhost without port",
+			hostStr:  "localhost",
+			wantHost: "localhost",
+			wantPort: "",
+		},
+
+		// Error cases
+		{
+			name:     "malformed brackets",
+			hostStr:  "[2001:db8::1:8006",
+			wantErr:  true,
+		},
+		{
+			name:     "brackets without closing with port attempt",
+			hostStr:  "[invalid:8006",
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotHost, gotPort, err := extractHostAndPort(tt.hostStr)
+			if tt.wantErr {
+				if err == nil {
+					t.Errorf("extractHostAndPort(%q) expected error, got host=%q port=%q", tt.hostStr, gotHost, gotPort)
+				}
+				return
+			}
+			if err != nil {
+				t.Errorf("extractHostAndPort(%q) unexpected error: %v", tt.hostStr, err)
+				return
+			}
+			if gotHost != tt.wantHost {
+				t.Errorf("extractHostAndPort(%q) host = %q, want %q", tt.hostStr, gotHost, tt.wantHost)
+			}
+			if gotPort != tt.wantPort {
+				t.Errorf("extractHostAndPort(%q) port = %q, want %q", tt.hostStr, gotPort, tt.wantPort)
+			}
+		})
+	}
+}
+
 func TestNormalizeNodeHost(t *testing.T) {
 	tests := []struct {
 		name     string