Fix PostgresUtils.isLocalhost()

This fixes a regression that was introduced with 6f96ff4

Author: bwaldvogel

src/main/java/de/cronn/postgres/snapshot/util/PostgresUtils.java

@@ -142,12 +142,21 @@ private static String prepareHostname(String host) {
 		}
 	}
 
-	private static boolean isLocalhost(String host) {
+	static boolean isLocalhost(String host) {
+		if (host.equals("localhost")) {
+			return true;
+		}
+		InetAddress inetAddress;
 		try {
-			InetAddress localHost = InetAddress.getLocalHost();
-			return localHost.getHostName().equals(host) || localHost.getHostAddress().equals(host);
+			inetAddress = InetAddress.getByName(host);
 		} catch (UnknownHostException e) {
-			throw new RuntimeException("Failed resolve localhost", e);
+			log.trace("Failed to resolve host '{}'", host, e);
+			return false;
+		}
+		try {
+			return InetAddress.getByName("localhost").equals(inetAddress);
+		} catch (UnknownHostException e) {
+			throw new RuntimeException(e);
 		}
 	}
 

src/test/java/de/cronn/postgres/snapshot/util/PostgresUtilsTest.java

@@ -2,9 +2,12 @@
 
 import static org.assertj.core.api.Assertions.*;
 
+import java.net.InetAddress;
 import java.net.URISyntaxException;
 
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 class PostgresUtilsTest {
 
@@ -23,6 +26,13 @@ void testParseConnectionInformation_unknownHost() {
 			.withMessage("org.postgresql.util.PSQLException: The connection attempt failed.");
 	}
 
+	@Test
+	void testParseConnectionInformation_failsToConnect() {
+		assertThatExceptionOfType(RuntimeException.class)
+			.isThrownBy(() -> PostgresUtils.parseConnectionInformation("jdbc:postgresql://10.0.0.1/test?connectTimeout=1", "user", "password"))
+			.withMessage("org.postgresql.util.PSQLException: The connection attempt failed.");
+	}
+
 	@Test
 	void testParseConnectionInformation_driverFailsToParseJdbcUrl() {
 		assertThatExceptionOfType(RuntimeException.class)
@@ -37,4 +47,18 @@ void testParseConnectionInformation_failToConnectToPostgresDatabase() {
 			.withMessage("org.postgresql.util.PSQLException: Connection to localhost:5432 refused." +
 						 " Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.");
 	}
+
+	@ParameterizedTest
+	@ValueSource(strings = { "localhost", "127.0.0.1" })
+	void testIsLocalHost_positive(String host) {
+		assertThat(PostgresUtils.isLocalhost(host)).isTrue();
+	}
+
+	@Test
+	void testIsLocalHost_negative() throws Exception {
+		assertThat(PostgresUtils.isLocalhost("some.host.local")).isFalse();
+		assertThat(PostgresUtils.isLocalhost("1.2.3.4")).isFalse();
+		InetAddress localHost = InetAddress.getLocalHost();
+		assertThat(PostgresUtils.isLocalhost(localHost.getHostName())).isFalse();
+	}
 }