Is there is any way to emulate database in Db Connections in UnitTests?

Oleg,

DbPsiFacade and DbDataSource are probably too high-level for a unit test.

Please provide a sample test source so we can figure out the right API for that.

Thanks for reply.

it is actually Functional tests if we follow terminology. In the documentation JetBrains says that most effective way is to use functional tests mostly, and I also like this approach.

Example test:

myFixture.configureByText(PhpFileType.INSTANCE,   "<?php \n" +
        "\\test\\PersonModel::find()->where('<caret>');");
myFixture.completeBasic();
assertEquals(5, myFixture.getLookupElementStrings().size());

(This method is located in com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase descendant.)
PersonModel is an ActiveRecord, plugin figure out database table and shows column names in <caret>.
Plugin finds table columns by traversing dataSources like that 

DbPsiFacade facade = DbPsiFacade.getInstance(project);
List<DbDataSource> dataSources = facade.getDataSources();
for (DbDataSource source : dataSources) {
     for (Object item : source.getModel().traverser().filter(DasTable.class)) {
            TableInfo tableInfo = new TableInfo((DasTable) item);
            for (DasColumn column : tableInfo.getColumns()) {
                list.add(DatabaseUtils.buildLookup(column, true, project));
      }
    }
}

I use following SetUp code:

@Override
protected void setUp() throws Exception {
    super.setUp();
    myFixture.configureFromExistingVirtualFile(myFixture.copyFileToProject("classes.php"));

    DbPsiFacade facade =  DbPsiFacade.getInstance(myFixture.getProject());
    if (facade.getDataSources().size() == 0) {
        TestDataSource source = new TestDataSource(myFixture.getProject());
        List<DbDataSource> dataSources = facade.getDataSources(); <- OperationNotSupported
        dataSources.add(source);
    }
}

List<DbDataSource> dataSources = facade.getDataSources(); <- OperationNotSupported

This line stopped working. I would like to find a "good" way to emulate database, so plugin gets fake database structure, and we can effectively test our plugin code.
Thanks.

For reference, one of affected files:
https://github.com/nvlad/yii2support/blob/master/tests/com/nvlad/yii2support/database/QueryTests.java

Please see https://youtrack.jetbrains.com/issue/IJSDK-328

Thanks a lot!