Test showing the #799 issue

xchart/src/test/java/org/knowm/xchart/XYChartTest.java

@@ -0,0 +1,29 @@
+package org.knowm.xchart;
+
+import java.io.ByteArrayOutputStream;
+import java.security.DigestOutputStream;
+import java.security.MessageDigest;
+import org.junit.jupiter.api.Disabled;
+
+public class XYChartTest {
+  private static final String digestType = "md5";
+
+  // https://github.com/knowm/XChart/issues/799
+  @Disabled // because the issue is not fixed yet
+  public void issue799() throws Exception {
+    // given
+    double[] xData = new double[] {0.0, 1.0, 2.0};
+    double[] yData = new double[] {2.0, 1.0, 0.0};
+    XYChart chart = QuickChart.getChart("Sample Chart", "X", "Y", "y(x)", xData, yData);
+    chart.getStyler().setyAxisTickLabelsFormattingFunction(yValue -> "1");
+
+    // when
+    DigestOutputStream output =
+        new DigestOutputStream(new ByteArrayOutputStream(), MessageDigest.getInstance(digestType));
+    BitmapEncoder.saveBitmap(chart, output, BitmapEncoder.BitmapFormat.PNG);
+    output.close();
+
+    // test
+    // finishes
+  }
+}