### Question:
BorderCorner { @NonNull abstract protected PointF getSharpCornerStart(); BorderCorner(float cornerRadius, float preBorderWidth, float postBorderWidth,
      @NonNull RectF borderBox, float angleBisector);   }### Answer:
@Test public void testGetSharpCornerStart() throws Exception { PointF topLeft = createBorderCorner(TOP_LEFT, 0, 10, 50, borderBox) .getSharpCornerStart(); assertThat(topLeft.x, is(0f)); assertThat(topLeft.y, is(25f)); PointF topRight = createBorderCorner(TOP_RIGHT, 0, 10, 50, borderBox) .getSharpCornerStart(); assertThat(topRight.x, is(375f)); assertThat(topRight.y, is(0f)); PointF bottomRight = createBorderCorner(BOTTOM_RIGHT, 0, 10, 50, borderBox) .getSharpCornerStart(); assertThat(bottomRight.x, is(400f)); assertThat(bottomRight.y, is(375f)); PointF bottomLeft = createBorderCorner(BOTTOM_LEFT, 0, 10, 50, borderBox) .getSharpCornerStart(); assertThat(bottomLeft.x, is(25f)); assertThat(bottomLeft.y, is(400f)); }