diff --git a/tests/testthat/test-CNVMetricsOverlapMethods.R b/tests/testthat/test-CNVMetricsOverlapMethods.R
index ea9a481..7cfdbfc 100644
--- a/tests/testthat/test-CNVMetricsOverlapMethods.R
+++ b/tests/testthat/test-CNVMetricsOverlapMethods.R
@@ -315,3 +315,39 @@ test_that("plotOverlapMetric() must return error when type==BOTH and filename gi
                  error_message)
 })
 
+test_that("plotOverlapMetric() must return a gtable when graph for amplification", {
+    
+    demo <- GRangesList()
+    demo[["sample01"]] <- GRanges(seqnames="chr1",
+                                  ranges=IRanges(start=c(100, 300, 800), end = c(200, 500, 900)), 
+                                  strand="*", state=c("AMPLIFICATION", "AMPLIFICATION", "DELETION"))
+    demo[["sample02"]] <- GRanges(seqnames="chr1",
+                                  ranges=IRanges(start=c(150, 600, 1000), end=c(250, 700, 1500)), 
+                                  strand="*", state=c("AMPLIFICATION", "AMPLIFICATION", "DELETION"))
+    
+    metric <- calculateOverlapMetric(segmentData = demo, 
+                                     method = "szymkiewicz")
+    
+    result <- plotOverlapMetric(metric=metric,  type="AMPLIFICATION")
+    
+    expect_is(object=result, class="gtable")
+})
+
+test_that("plotOverlapMetric() must return a gtable when graph for deletion", {
+    
+    demo <- GRangesList()
+    demo[["sample01"]] <- GRanges(seqnames="chr1",
+                                  ranges=IRanges(start=c(100, 300, 800), end = c(200, 500, 900)), 
+                                  strand="*", state=c("AMPLIFICATION", "AMPLIFICATION", "DELETION"))
+    demo[["sample02"]] <- GRanges(seqnames="chr1",
+                                  ranges=IRanges(start=c(150, 600, 1000), end=c(250, 700, 1500)), 
+                                  strand="*", state=c("AMPLIFICATION", "AMPLIFICATION", "DELETION"))
+    
+    metric <- calculateOverlapMetric(segmentData = demo, 
+                                     method = "szymkiewicz")
+    
+    result <- plotOverlapMetric(metric=metric,  type="DELETION")
+    
+    expect_is(object=result, class="gtable")
+})
+