Rename three test classes so Surefire runs them

src/test/java/org/apache/commons/imaging/formats/png/PngWriteForceTrueColorText.java → src/test/java/org/apache/commons/imaging/formats/png/PngWriteForceTrueColorTest.java

@@ -27,7 +27,7 @@
 import org.apache.commons.imaging.internal.Debug;
 import org.junit.jupiter.api.Test;
 
-public class PngWriteForceTrueColorText extends AbstractPngTest {
+public class PngWriteForceTrueColorTest extends AbstractPngTest {
 
     @Test
     void test() throws Exception {

src/test/java/org/apache/commons/imaging/roundtrip/FullColorRoundtrip.java → src/test/java/org/apache/commons/imaging/roundtrip/FullColorRoundtripTest.java

@@ -24,7 +24,7 @@
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
-public class FullColorRoundtrip extends RoundtripBase {
+public class FullColorRoundtripTest extends RoundtripBase {
 
     public static final BufferedImage[] images = { TestImages.createFullColorImage(1, 1), // minimal
             TestImages.createFullColorImage(2, 2), //

src/test/java/org/apache/commons/imaging/roundtrip/PixelDensityRoundtrip.java → src/test/java/org/apache/commons/imaging/roundtrip/PixelDensityRoundtripTest.java

@@ -31,7 +31,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 
-public class PixelDensityRoundtrip extends RoundtripBase {
+public class PixelDensityRoundtripTest extends RoundtripBase {
 
     public static Stream<FormatInfo> testPixelDensityRoundtrip() {
         return Stream.of(FormatInfo.PRESERVING_RESOLUTION_FORMATS);