added mising docs and modify TlsConfig method

Author: MitulShah1

docs/modules/cassandra.md

@@ -70,6 +70,23 @@ In the case you have a custom config file for Cassandra, it's possible to copy t
 !!!warning
     You should provide a valid Cassandra configuration file, otherwise the container will fail to start.
 
+#### WithTLS
+
+- Not available until the next release <a href="https://github.com/testcontainers/testcontainers-go"><span class="tc-version">:material-tag: main</span></a>
+
+If you need to enable TLS/SSL encryption for client connections, you can use the `cassandra.WithTLS()` option. 
+
+When enabled, the container will:
+- Generate self-signed certificates automatically
+- Configure Cassandra to use client encryption
+- Expose the SSL port (9142)
+
+Use the `TLSConfig()` method on the returned container to get the `*tls.Config` for client connections. The method returns an error if TLS was not enabled via `WithTLS()`.
+
+<!--codeinclude-->
+[Using TLS option](../../modules/cassandra/cassandra_test.go) inside_block:withTLS
+<!--/codeinclude-->
+
 {% include "../features/common_functional_options_list.md" %}
 
 ### Container Methods

modules/cassandra/cassandra.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"crypto/tls"
 	_ "embed"
+	"errors"
 	"fmt"
 	"io"
 	"path/filepath"
@@ -38,9 +39,12 @@ func (c *CassandraContainer) ConnectionHost(ctx context.Context) (string, error)
 }
 
 // TLSConfig returns the TLS configuration for secure client connections.
-// Returns nil if TLS is not enabled on the container.
-func (c *CassandraContainer) TLSConfig() *tls.Config {
-	return c.settings.tlsConfig
+// Returns an error if TLS is not enabled on the container.
+func (c *CassandraContainer) TLSConfig() (*tls.Config, error) {
+	if !c.settings.tlsEnabled {
+		return nil, errors.New("TLS is not enabled on this container")
+	}
+	return c.settings.tlsConfig, nil
 }
 
 // WithConfigFile sets the YAML config file to be used for the cassandra container

modules/cassandra/cassandra_test.go

@@ -128,7 +128,8 @@ func TestCassandraWithTLS(t *testing.T) {
 	require.NoError(t, err)
 
 	// Verify TLS config is available
-	tlsConfig := ctr.TLSConfig()
+	tlsConfig, err := ctr.TLSConfig()
+	require.NoError(t, err)
 	require.NotNil(t, tlsConfig, "TLSConfig should not be nil when TLS is enabled")
 
 	// Get SSL connection host

modules/cassandra/examples_test.go

@@ -103,7 +103,11 @@ func ExampleRun_withTLS() {
 	}
 
 	// Get TLS config for secure connection
-	tlsConfig := cassandraContainer.TLSConfig()
+	tlsConfig, err := cassandraContainer.TLSConfig()
+	if err != nil {
+		log.Printf("failed to get TLS config: %s", err)
+		return
+	}
 	// }
 
 	cluster := gocql.NewCluster(connectionHost)