diff --git a/skabandclient/skabandclient_test.go b/skabandclient/skabandclient_test.go
new file mode 100644
index 0000000..4ed83d4
--- /dev/null
+++ b/skabandclient/skabandclient_test.go
@@ -0,0 +1,118 @@
+package skabandclient
+
+import (
+	"testing"
+)
+
+// TestValidateSessionID_Roundtrip tests that all session IDs generated by NewSessionID
+// pass validation by ValidateSessionID
+func TestValidateSessionID_Roundtrip(t *testing.T) {
+	// Test multiple generated session IDs to ensure consistent behavior
+	for i := range 1000 {
+		sessionID := NewSessionID()
+		if !ValidateSessionID(sessionID) {
+			t.Errorf("Generated session ID %q failed validation (iteration %d)", sessionID, i)
+		}
+	}
+}
+
+// TestValidateSessionID_ValidCases tests various valid session ID formats
+func TestValidateSessionID_ValidCases(t *testing.T) {
+	tests := []struct {
+		name      string
+		sessionID string
+		want      bool
+	}{
+		{"uppercase letters", "ABCD-EFGH-JKMN-PQRS", true},
+		{"lowercase letters", "abcd-efgh-jkmn-pqrs", true},
+		{"mixed case", "AbCd-EfGh-JkMn-PqRs", true},
+		{"with numbers", "123A-5678-9BCD-EF0H", true},
+		{"all numbers", "1234-5678-9012-3456", true},
+		{"boundary chars lower", "0000-0000-0000-0000", true},
+		{"boundary chars upper A-H", "ABCD-EFGH-ABCD-EFGH", true},
+		{"boundary chars J-N", "JKMN-JKMN-JKMN-JKMN", true},
+		{"boundary chars P-Z", "PQRS-TUVW-XYZ0-1234", true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ValidateSessionID(tt.sessionID)
+			if got != tt.want {
+				t.Errorf("ValidateSessionID(%q) = %v, want %v", tt.sessionID, got, tt.want)
+			}
+		})
+	}
+}
+
+// TestValidateSessionID_InvalidCases tests various invalid session ID formats
+func TestValidateSessionID_InvalidCases(t *testing.T) {
+	tests := []struct {
+		name      string
+		sessionID string
+		want      bool
+	}{
+		{"empty string", "", false},
+		{"too short", "ABC-DEF-GHI-JKL", false},
+		{"too long", "ABCDE-EFGH-JKMN-PQRS", false},
+		{"missing dashes", "ABCDEFGHJKMNPQRS", false},
+		{"wrong dash positions", "AB-CD-EFGH-JKMNPQRS", false},
+		{"invalid chars I", "ABCI-EFGH-JKMN-PQRS", false},
+		{"invalid chars O", "ABCO-EFGH-JKMN-PQRS", false},
+		{"invalid chars lowercase i", "ABCi-EFGH-JKMN-PQRS", false},
+		{"invalid chars lowercase o", "ABCo-EFGH-JKMN-PQRS", false},
+		{"special characters", "ABC!-EFGH-JKMN-PQRS", false},
+		{"spaces", "ABC -EFGH-JKMN-PQRS", false},
+		{"extra dashes", "ABCD--EFGH-JKMN-PQRS", false},
+		{"underscore instead of dash", "ABCD_EFGH_JKMN_PQRS", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ValidateSessionID(tt.sessionID)
+			if got != tt.want {
+				t.Errorf("ValidateSessionID(%q) = %v, want %v", tt.sessionID, got, tt.want)
+			}
+		})
+	}
+}
+
+// TestNewSessionID_Format tests that NewSessionID generates properly formatted IDs
+func TestNewSessionID_Format(t *testing.T) {
+	// Generate multiple session IDs and verify they all have the correct format
+	for range 100 {
+		sessionID := NewSessionID()
+
+		// Check length
+		if len(sessionID) != 19 { // xxxx-xxxx-xxxx-xxxx = 19 characters
+			t.Errorf("Generated session ID %q has wrong length %d, expected 19", sessionID, len(sessionID))
+		}
+
+		// Check dash positions
+		if sessionID[4] != '-' || sessionID[9] != '-' || sessionID[14] != '-' {
+			t.Errorf("Generated session ID %q has wrong dash positions", sessionID)
+		}
+
+		// Should pass validation
+		if !ValidateSessionID(sessionID) {
+			t.Errorf("Generated session ID %q failed validation", sessionID)
+		}
+	}
+}
+
+// TestNewSessionID_Uniqueness tests that NewSessionID generates unique IDs
+func TestNewSessionID_Uniqueness(t *testing.T) {
+	seen := make(map[string]bool)
+	count := 10000
+
+	for range count {
+		sessionID := NewSessionID()
+		if seen[sessionID] {
+			t.Errorf("Duplicate session ID generated: %q", sessionID)
+		}
+		seen[sessionID] = true
+	}
+
+	if len(seen) != count {
+		t.Errorf("Expected %d unique session IDs, got %d", count, len(seen))
+	}
+}