Update to DataDiffSectionSpecTest.java is needed when Litho upgrades RecyclerView support lib version to 1.2.0-alpha02 or newer

[yuntao]

Litho currently depends on androidx.recyclerview:recyclerview:1.0.0 in build.gradle.

In RecyclerView support lib 1.2.0-alpha02, a fix was made to DiffUtil. This will cause Litho's DataDiffSectionSpecTest.java to fail. The following change is needed:

Before:

@Test
public void testMoveData() {
    ...
    assertOperation(newOperation1, MOVE, 1, 0, 1, "1", "1");
    ...
    assertOperation(newOperation2, MOVE, 2, 0, 1, "2", "2");
}

After:

@Test
public void testMoveData() {
    ...
    assertOperation(newOperation1, MOVE, 1, 2, 1, "1", "1");
    ...
    assertOperation(newOperation2, MOVE, 0, 2, 1, "0", "0");
}

This test case verifies the operations done to modify a RecyclerView list from [0, 1, 2] to [2, 1, 0]. Prior to the DiffUtil fix, the two move operations done were [0, 1, 2] -> [1, 0, 2] -> [2, 1, 0]. Now the two move operations are [0, 1, 2] -> [0, 2, 1] -> [2, 1, 0].

In summary, when Litho upgrades RecyclerView support lib to 1.2.0-alpha02 or newer, DataDiffSectionSpecTest.java will fail and need to be updated according to the above.

I noticed that testMoveData() has been removed due to this exact reason in commit f3e4dbe very recently. The test could be reinstated with the above changes. CC @sturmen

[adityasharat]

We are on it.