fix(tests): use shared Docker network for CI compatibility

- Replace host.docker.internal with shared network approach
- Containers now communicate via container names on a shared network
- Works on both Docker Desktop and Linux CI (GitHub Actions)
- Generate unique network/container names per test for isolation
- Update README with new networking pattern

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: j7nw4r

README.md

@@ -19,31 +19,41 @@ tokio = { version = "1", features = ["full"] }
 ## Quick Start
 
 ```rust
-use supabase_testcontainers_modules::{Auth, AUTH_PORT, DOCKER_INTERNAL_HOST, LOCAL_HOST};
+use supabase_testcontainers_modules::{Auth, AUTH_PORT, LOCAL_HOST};
 use testcontainers::{runners::AsyncRunner, ImageExt};
 use testcontainers_modules::postgres::Postgres;
 
 #[tokio::test]
 async fn test_auth() -> anyhow::Result<()> {
-    // Start PostgreSQL (requires version 12+)
-    let postgres = Postgres::default().with_tag("15-alpine").start().await?;
+    // Use shared network for container-to-container communication
+    let network = "test-network";
+    let pg_container = "postgres-db";
+
+    // Start PostgreSQL 15 on shared network
+    let postgres = Postgres::default()
+        .with_tag("15-alpine")
+        .with_network(network)
+        .with_container_name(pg_container)
+        .start()
+        .await?;
     let pg_port = postgres.get_host_port_ipv4(5432).await?;
 
-    // Connection strings
+    // Auth connects via container name, schema init via localhost
     let auth_db_url = format!(
-        "postgres://supabase_auth_admin:password@{}:{}/postgres",
-        DOCKER_INTERNAL_HOST, pg_port
+        "postgres://supabase_auth_admin:password@{}:5432/postgres",
+        pg_container
     );
     let local_db_url = format!(
         "postgres://postgres:postgres@{}:{}/postgres",
         LOCAL_HOST, pg_port
     );
 
-    // Start Auth container
+    // Initialize schema and start Auth on same network
     let auth = Auth::default()
         .with_db_url(&auth_db_url)
         .init_db_schema(&local_db_url, "password")
         .await?
+        .with_network(network)
         .start()
         .await?;
 

tests/auth_integration.rs

@@ -4,14 +4,18 @@
 //! Run with: `cargo test --features auth,const --test auth_integration`
 
 use anyhow::Result;
-use supabase_testcontainers_modules::{Auth, AUTH_PORT, DOCKER_INTERNAL_HOST, LOCAL_HOST};
+use supabase_testcontainers_modules::{Auth, AUTH_PORT, LOCAL_HOST};
 use testcontainers::runners::AsyncRunner;
 use testcontainers::{ContainerAsync, ImageExt};
 use testcontainers_modules::postgres::Postgres;
 use tokio_postgres::NoTls;
 
 /// PostgreSQL port constant
 const POSTGRES_PORT: u16 = 5432;
+/// Network name for container-to-container communication
+const TEST_NETWORK: &str = "supabase-test-network";
+/// PostgreSQL container alias on the shared network
+const POSTGRES_ALIAS: &str = "postgres";
 
 /// Helper struct containing both containers and connection info
 pub struct AuthTestContext {
@@ -42,14 +46,27 @@ pub struct AuthTestContext {
 /// // Containers are automatically stopped when ctx goes out of scope
 /// ```
 pub async fn setup_auth_with_postgres() -> Result<AuthTestContext> {
-    // Start PostgreSQL 15 container (Auth migrations require PostgreSQL 12+ for generated columns)
-    let postgres = Postgres::default().with_tag("15-alpine").start().await?;
+    // Generate unique network and container names for test isolation
+    let test_id = std::time::SystemTime::now()
+        .duration_since(std::time::UNIX_EPOCH)
+        .unwrap()
+        .as_nanos();
+    let network_name = format!("{}-{}", TEST_NETWORK, test_id);
+    let postgres_name = format!("{}-{}", POSTGRES_ALIAS, test_id);
+
+    // Start PostgreSQL 15 on shared network with a known container name
+    let postgres = Postgres::default()
+        .with_tag("15-alpine")
+        .with_network(&network_name)
+        .with_container_name(&postgres_name)
+        .start()
+        .await?;
     let postgres_port = postgres.get_host_port_ipv4(POSTGRES_PORT).await?;
 
-    // Connection string for Auth container (uses docker internal host)
+    // Connection string for Auth container (uses container name on shared network)
     let auth_db_url = format!(
         "postgres://supabase_auth_admin:testpassword@{}:{}/postgres",
-        DOCKER_INTERNAL_HOST, postgres_port
+        postgres_name, POSTGRES_PORT
     );
 
     // Connection string for schema init (uses localhost from host machine)
@@ -58,14 +75,15 @@ pub async fn setup_auth_with_postgres() -> Result<AuthTestContext> {
         LOCAL_HOST, postgres_port
     );
 
-    // Initialize Auth with database schema and start container
+    // Initialize Auth with database schema and start container on same network
     let auth = Auth::default()
         .with_db_url(&auth_db_url)
         .with_mailer_autoconfirm(true)
         .with_sms_autoconfirm(true)
         .with_anonymous_users(true)
         .init_db_schema(&local_db_url, "testpassword")
         .await?
+        .with_network(&network_name)
         .start()
         .await?;
 
@@ -180,25 +198,39 @@ mod tests {
     /// Test that signup is rejected when disabled
     #[tokio::test]
     async fn test_signup_rejected_when_disabled() -> Result<()> {
-        // Start PostgreSQL 15 container (Auth migrations require PostgreSQL 12+)
-        let postgres = Postgres::default().with_tag("15-alpine").start().await?;
+        // Generate unique network and container names for test isolation
+        let test_id = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos();
+        let network_name = format!("{}-{}", TEST_NETWORK, test_id);
+        let postgres_name = format!("{}-{}", POSTGRES_ALIAS, test_id);
+
+        // Start PostgreSQL 15 on shared network
+        let postgres = Postgres::default()
+            .with_tag("15-alpine")
+            .with_network(&network_name)
+            .with_container_name(&postgres_name)
+            .start()
+            .await?;
         let postgres_port = postgres.get_host_port_ipv4(POSTGRES_PORT).await?;
 
         let auth_db_url = format!(
             "postgres://supabase_auth_admin:testpassword@{}:{}/postgres",
-            DOCKER_INTERNAL_HOST, postgres_port
+            postgres_name, POSTGRES_PORT
         );
         let local_db_url = format!(
             "postgres://postgres:postgres@{}:{}/postgres",
             LOCAL_HOST, postgres_port
         );
 
-        // Create Auth with signup disabled
+        // Create Auth with signup disabled on same network
         let auth = Auth::default()
             .with_db_url(&auth_db_url)
             .with_signup_disabled(true)
             .init_db_schema(&local_db_url, "testpassword")
             .await?
+            .with_network(&network_name)
             .start()
             .await?;