Conditionally disable unit tests for PostgreSQL and MySQL

junit introduced Assume functionality to conditionaly skipping tests execution.
Use it to conditionaly skip tests for databases that may not be installed or
configured on current machine:

Running com.google.gwtorm.schema.sql.DialectPostgreSQLTest
Tests run: 4, Failures: 0, Errors: 0, Skipped: 4, Time elapsed: 0.015 sec

"Skipped: 4" indicates here that the tests were skipped, because of Assume
assumption was not satisfied.

Change-Id: If4ae2aaec944bc4035906dbdf677da84d734e1c6
diff --git a/src/test/java/com/google/gwtorm/schema/sql/DialectMySQLTest.java b/src/test/java/com/google/gwtorm/schema/sql/DialectMySQLTest.java
index 48aa8fc..89ebeeb 100644
--- a/src/test/java/com/google/gwtorm/schema/sql/DialectMySQLTest.java
+++ b/src/test/java/com/google/gwtorm/schema/sql/DialectMySQLTest.java
@@ -18,6 +18,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeNoException;
 
 import com.google.gwtorm.data.PhoneBookDb;
 import com.google.gwtorm.data.PhoneBookDb2;
@@ -57,7 +58,11 @@
     final String pass = "gwtorm";
 
     final String url = "jdbc:mysql://" + host + "/" + database;
-    db = DriverManager.getConnection(url, user, pass);
+    try {
+      db = DriverManager.getConnection(url, user, pass);
+    } catch (Throwable t) {
+      assumeNoException(t);
+    }
     executor = new JdbcExecutor(db);
     dialect = new DialectMySQL().refine(db);
 
diff --git a/src/test/java/com/google/gwtorm/schema/sql/DialectPostgreSQLTest.java b/src/test/java/com/google/gwtorm/schema/sql/DialectPostgreSQLTest.java
index 07bb465..2957113 100644
--- a/src/test/java/com/google/gwtorm/schema/sql/DialectPostgreSQLTest.java
+++ b/src/test/java/com/google/gwtorm/schema/sql/DialectPostgreSQLTest.java
@@ -18,6 +18,7 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeNoException;
 
 import com.google.gwtorm.data.PhoneBookDb;
 import com.google.gwtorm.data.PhoneBookDb2;
@@ -55,7 +56,11 @@
     final String user = "gwtorm";
     final String pass = "gwtorm";
 
-    db = DriverManager.getConnection("jdbc:postgresql:" + database, user, pass);
+    try {
+      db = DriverManager.getConnection("jdbc:postgresql:" + database, user, pass);
+    } catch (Throwable t) {
+      assumeNoException(t);
+    }
     executor = new JdbcExecutor(db);
     dialect = new DialectPostgreSQL().refine(db);