#29 - Use Testcontainers to run Postgres integration tests.

Postgres integration tests now run either with a locally installed and started database or if no such database can be found an instance gets started in a Docker container via Testcontainers. We prefer a database based on TestContainers. Only if this can't be obtained do we try to access a local database for Postgres. This minimizes the risk of accessing a database during tests that is not intended for that purpose. If the system property `spring.data.r2dbc.test.preferLocalDatabase` is set to "true" the local database is preferred. Original pull request: #51.

Author: schauder

src/test/java/org/springframework/data/r2dbc/testing/ExternalDatabase.java

@@ -24,6 +24,8 @@
 
 import org.junit.AssumptionViolatedException;
 import org.junit.rules.ExternalResource;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * {@link ExternalResource} wrapper to encapsulate {@link ProvidedDatabase} and
@@ -33,6 +35,8 @@
  */
 public abstract class ExternalDatabase extends ExternalResource {
 
+private static Logger LOG = LoggerFactory.getLogger(ExternalDatabase.class);
+
 /**
  * @return the post of the database service.
  */
@@ -53,16 +57,35 @@ public abstract class ExternalDatabase extends ExternalResource {
  */
 public abstract String getUsername();
 
+/**
+ * Throws an {@link AssumptionViolatedException} if the database cannot be reached.
+ */
 @Override
 protected void before() {
 
+if (!checkValidity()) {
+throw new AssumptionViolatedException(
+String.format("Cannot connect to %s:%d. Skipping tests.", getHostname(), getPort()));
+}
+}
+
+/**
+ * performs a test if the database can actually be reached.
+ *
+ * @return true, if the database could be reached.
+ */
+boolean checkValidity() {
+
 try (Socket socket = new Socket()) {
+
 socket.connect(new InetSocketAddress(getHostname(), getPort()), Math.toIntExact(TimeUnit.SECONDS.toMillis(5)));
+return true;
 
 } catch (IOException e) {
-throw new AssumptionViolatedException(
-String.format("Cannot connect to %s:%d. Skipping tests.", getHostname(), getPort()));
+LOG.debug("external database not available.", e);
 }
+
+return false;
 }
 
 /**
@@ -122,4 +145,42 @@ public String getPassword() {
 return password;
 }
 }
+
+/**
+ * An {@link ExternalDatabase} that couldn't get constructed.
+ *
+ * @author Jens Schauder
+ */
+static class NoSuchDatabase extends ExternalDatabase {
+
+@Override
+boolean checkValidity() {
+return false;
+}
+
+@Override
+public int getPort() {
+throw new UnsupportedOperationException();
+}
+
+@Override
+public String getHostname() {
+throw new UnsupportedOperationException();
+}
+
+@Override
+public String getDatabase() {
+throw new UnsupportedOperationException();
+}
+
+@Override
+public String getUsername() {
+throw new UnsupportedOperationException();
+}
+
+@Override
+public String getPassword() {
+throw new UnsupportedOperationException();
+}
+}
 }

src/test/java/org/springframework/data/r2dbc/testing/PostgresTestSupport.java

@@ -4,18 +4,24 @@
 import io.r2dbc.postgresql.PostgresqlConnectionFactory;
 import io.r2dbc.spi.ConnectionFactory;
 
+import java.util.function.Supplier;
+
 import javax.sql.DataSource;
 
 import org.postgresql.ds.PGSimpleDataSource;
 import org.springframework.data.r2dbc.testing.ExternalDatabase.ProvidedDatabase;
+import org.testcontainers.containers.PostgreSQLContainer;
 
 /**
  * Utility class for testing against Postgres.
  *
  * @author Mark Paluch
+ * @author Jens Schauder
  */
 public class PostgresTestSupport {
 
+private static ExternalDatabase testContainerDatabase;
+
 public static String CREATE_TABLE_LEGOSET = "CREATE TABLE legoset (\n" //
 + " id integer CONSTRAINT id PRIMARY KEY,\n" //
 + " name varchar(255) NOT NULL,\n" //
@@ -31,30 +37,91 @@ public class PostgresTestSupport {
 public static String INSERT_INTO_LEGOSET = "INSERT INTO legoset (id, name, manual) VALUES($1, $2, $3)";
 
 /**
- * Returns a locally provided database at {@code postgres:@localhost:5432/postgres}.
+ * Returns a database either hosted locally at {@code postgres:@localhost:5432/postgres} or running inside Docker.
  *
- * @return
+ * @return information about the database. Guaranteed to be not {@literal null}.
  */
 public static ExternalDatabase database() {
-return local();
+
+if (Boolean.getBoolean("spring.data.r2dbc.test.preferLocalDatabase")) {
+
+return getFirstWorkingDatabase( //
+PostgresTestSupport::local, //
+PostgresTestSupport::testContainer //
+);
+} else {
+
+return getFirstWorkingDatabase( //
+PostgresTestSupport::testContainer, //
+PostgresTestSupport::local //
+);
+}
+}
+
+private static ExternalDatabase getFirstWorkingDatabase(Supplier<ExternalDatabase> first,
+Supplier<ExternalDatabase> second) {
+
+ExternalDatabase database = first.get();
+if (database.checkValidity()) {
+return database;
+} else {
+return second.get();
+}
 }
 
 /**
  * Returns a locally provided database at {@code postgres:@localhost:5432/postgres}.
- *
- * @return
  */
 private static ExternalDatabase local() {
-return ProvidedDatabase.builder().hostname("localhost").port(5432).database("postgres").username("postgres")
+
+return ProvidedDatabase.builder() //
+.hostname("localhost") //
+.port(5432) //
+.database("postgres") //
+.username("postgres") //
 .password("").build();
 }
 
+/**
+ * Returns a database provided via Testcontainers.
+ */
+private static ExternalDatabase testContainer() {
+
+if (testContainerDatabase == null) {
+
+try {
+PostgreSQLContainer postgreSQLContainer = new PostgreSQLContainer();
+postgreSQLContainer.start();
+
+testContainerDatabase = ProvidedDatabase.builder() //
+.hostname("localhost") //
+.port(postgreSQLContainer.getFirstMappedPort()) //
+.database(postgreSQLContainer.getDatabaseName()) //
+.username(postgreSQLContainer.getUsername()) //
+.password(postgreSQLContainer.getPassword()).build();
+
+} catch (IllegalStateException ise) {
+// docker is not available.
+testContainerDatabase = new ExternalDatabase.NoSuchDatabase();
+}
+
+}
+
+return testContainerDatabase;
+}
+
 /**
  * Creates a new {@link ConnectionFactory} configured from the {@link ExternalDatabase}..
  */
 public static ConnectionFactory createConnectionFactory(ExternalDatabase database) {
-return new PostgresqlConnectionFactory(PostgresqlConnectionConfiguration.builder().host(database.getHostname())
-.database(database.getDatabase()).username(database.getUsername()).password(database.getPassword()).build());
+
+return new PostgresqlConnectionFactory(PostgresqlConnectionConfiguration.builder() //
+.host(database.getHostname()) //
+.database(database.getDatabase()) //
+.port(database.getPort()) //
+.username(database.getUsername()) //
+.password(database.getPassword()) //
+.build());
 }
 
 /**
@@ -72,4 +139,5 @@ public static DataSource createDataSource(ExternalDatabase database) {
 
 return dataSource;
 }
+
 }

src/test/java/org/springframework/data/r2dbc/testing/SqlServerTestSupport.java

@@ -33,31 +33,35 @@ public class SqlServerTestSupport {
 
 /**
  * Returns a locally provided database at {@code sqlserver:@localhost:1433/master}.
- *
- * @return
  */
 public static ExternalDatabase database() {
 return local();
 }
 
 /**
- * Returns a locally provided database at {@code postgres:@localhost:5432/postgres}.
- *
- * @return
+ * Returns a locally provided database at {@code sqlserver:@localhost:1433/master}.
  */
 private static ExternalDatabase local() {
-return ProvidedDatabase.builder().hostname("localhost").port(1433).database("master").username("sa")
-.password("A_Str0ng_Required_Password").build();
+
+return ProvidedDatabase.builder() //
+.hostname("localhost") //
+.port(1433) //
+.database("master") //
+.username("sa") //
+.password("A_Str0ng_Required_Password") //
+.build();
 }
 
 /**
  * Creates a new {@link ConnectionFactory} configured from the {@link ExternalDatabase}..
  */
 public static ConnectionFactory createConnectionFactory(ExternalDatabase database) {
+
 return new MssqlConnectionFactory(MssqlConnectionConfiguration.builder().host(database.getHostname()) //
 .database(database.getDatabase()) //
 .username(database.getUsername()) //
 .password(database.getPassword()) //
+.port(database.getPort()) //
 .build());
 }