diff --git a/src/test/java/hudson/plugins/jacococoveragecolumn/AbstractJaCoCoCoverageColumnTest.java b/src/test/java/hudson/plugins/jacococoveragecolumn/AbstractJaCoCoCoverageColumnTest.java
index db71d6f6..8574f60f 100644
--- a/src/test/java/hudson/plugins/jacococoveragecolumn/AbstractJaCoCoCoverageColumnTest.java
+++ b/src/test/java/hudson/plugins/jacococoveragecolumn/AbstractJaCoCoCoverageColumnTest.java
@@ -89,9 +89,10 @@ public MyRun getLastSuccessfulBuild() {
 				}
 			}
 
-			@Override
-			protected synchronized void saveNextBuildNumber() {
-			}
+            @Override
+            public int assignBuildNumber() throws IOException {
+                return nextBuildNumber++;
+            }
 		};
 		assertTrue(abstractJaCoCoCoverageColumn.hasCoverage(mockJob));
 		assertEquals("66.67", abstractJaCoCoCoverageColumn.getPercent(mockJob));
@@ -218,8 +219,9 @@ public MyRun getLastSuccessfulBuild() {
         }
 
         @Override
-		protected synchronized void saveNextBuildNumber() {
-		}
+        public int assignBuildNumber() throws IOException {
+            return nextBuildNumber++;
+        }
 	}
 	
 	private class MyJob extends Job<MyJob,MyRun> {
diff --git a/src/test/java/hudson/plugins/jacococoveragecolumn/BranchCoverageColumnTest.java b/src/test/java/hudson/plugins/jacococoveragecolumn/BranchCoverageColumnTest.java
index 64f07a9c..fff653f6 100644
--- a/src/test/java/hudson/plugins/jacococoveragecolumn/BranchCoverageColumnTest.java
+++ b/src/test/java/hudson/plugins/jacococoveragecolumn/BranchCoverageColumnTest.java
@@ -57,9 +57,10 @@ public MyRun getLastSuccessfulBuild() {
 				}
 			}
 
-			@Override
-			protected synchronized void saveNextBuildNumber() {
-			}
+            @Override
+            public int assignBuildNumber() throws IOException {
+                return nextBuildNumber++;
+            }
 		};
 		assertEquals("66.67", sut.getPercent(mockJob));
 
diff --git a/src/test/java/hudson/plugins/jacococoveragecolumn/JaCoCoColumnTest.java b/src/test/java/hudson/plugins/jacococoveragecolumn/JaCoCoColumnTest.java
index 52aeb99c..b31ef78e 100644
--- a/src/test/java/hudson/plugins/jacococoveragecolumn/JaCoCoColumnTest.java
+++ b/src/test/java/hudson/plugins/jacococoveragecolumn/JaCoCoColumnTest.java
@@ -56,9 +56,10 @@ public MyRun getLastSuccessfulBuild() {
 				}
 			}
 
-			@Override
-			protected synchronized void saveNextBuildNumber() {
-			}
+            @Override
+            public int assignBuildNumber() throws IOException {
+                return nextBuildNumber++;
+            }
 		};
 		assertTrue(jaCoCoColumn.hasCoverage(mockJob));
 		assertEquals("33.33", jaCoCoColumn.getPercent(mockJob));