diff --git a/samples/sample_copy_path_flat.jl b/samples/sample_copy_path_flat.jl
index f053cf8..a95769b 100644
--- a/samples/sample_copy_path_flat.jl
+++ b/samples/sample_copy_path_flat.jl
@@ -40,7 +40,7 @@ for x in opath
     end
     s1 = repr(x.points)
     move_to(cr,10.0,16.0+(14.0*l))
-    l += 1
+    global l += 1
     show_text(cr,s0*s1)
 end
 
@@ -59,7 +59,7 @@ for x in fpath
     end
     s1 = repr(x.points)
     move_to(cr,10.0,50.0+(14.0*l))
-    l += 1
+    global l += 1
     show_text(cr,s0*s1)
 end
 
diff --git a/samples/sample_script0.jl b/samples/sample_script0.jl
index 079c663..4993be1 100644
--- a/samples/sample_script0.jl
+++ b/samples/sample_script0.jl
@@ -48,7 +48,7 @@ t1 = 24.0
 for x in r1
     move_to(cr,0.0,t1)
     show_text(cr,x)
-    t1 += 12.0
+    global t1 += 12.0
 end
 
 
diff --git a/test/runtests.jl b/test/runtests.jl
index 6fa4cc0..51f6039 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -78,8 +78,11 @@ end
     end
 
     @testset "sample: $test_file_name" for test_file_name in samples_files
-        mod = Module(Symbol(test_file_name))
+        # Run each sample script in a separate module to avoid pollution
+        s   = Symbol(test_file_name)
+        mod = @eval(Main, module $s end)
         @eval mod include($(joinpath(samples_dir_path, test_file_name)))
+
         output_png_name = replace(test_file_name,".jl",".png")
         @test isfile(output_png_name)
         rm(output_png_name)