Overview

The migration is pretty straightforward:

create new test file in `xxx/tests/yyy_test.php`
copy contents of the old test file
replace extends UnitTestCase with extends basic_testcase and extends UnitTestCaseUsingDatabase with extends advanced_testcase
move constructor code to setUp
fix setUp(), tearDown()
fix assert syntax
add $this->resetAfterTest() in advanced test cases that modify database
add missing global $CFG for includes outside of testcase classes

Assert differences

SimpleTest	PHPUnit	Notes
`$this->assertEqual($expected, $actual)`	`$this->assertEquals($expected, $actual)`
`$this->assertNotEqual($expected, $actual)`	`$this->assertNotEquals($expected, $actual)`
`$this->assertWithinMargin($expected, $actual, $margin)`	`$this->assertEquals($expected, $actual, , $margin)`
`$this->assertIdentical($expected, $actual)`	`$this->assertSame($expected, $actual)`
`$this->assertNotIdentical($expected, $actual)`	`$this->assertNotSame($expected, $actual)`
`$this->assertTrue($actual)`	`$this->assertTrue((bool)$a, $b)`	SimpleTest converts parameter to bool.
`$this->assertFalse($actual)`	`$this->assertFalse((bool)$a, $b)`	SimpleTest converts parameter to bool.
`$this->assertIsA($actual, $classname)`	`$this->assertInstanceOf($classname, $actual)`	Only objects.
`$this->assertIsA($actual, 'array')`	`$this->assertEquals('array', gettype($actual)`	Other data types.
`$this->expectException(true)`	`$this->setExpectedException('exception_name')`
`$this->expectError()`	`$this->setExpectedException('PHPUnit_Framework_Error')`