diff --git a/tests/test_ext_graphviz.py b/tests/test_ext_graphviz.py
index 53f5be4df..d0cbbc42f 100644
--- a/tests/test_ext_graphviz.py
+++ b/tests/test_ext_graphviz.py
@@ -10,14 +10,17 @@
 """
 
 import re
-from util import with_app
+
+from util import with_app, SkipTest
 
 
 @with_app('html', testroot='ext-graphviz')
 def test_graphviz(app, status, warning):
     app.builder.build_all()
-    if "dot command 'dot' cannot be run" not in warning.getvalue():
-        content = (app.outdir / 'index.html').text()
-        html = ('<p class="graphviz">\s*<img .*?/>\s*</p>\s*'
-                '<p class="caption"><span class="caption-text">caption of graph</span>')
-        assert re.search(html, content, re.S)
+    if "dot command 'dot' cannot be run" in warning.getvalue():
+        raise SkipTest('graphviz "dot" is not available')
+
+    content = (app.outdir / 'index.html').text()
+    html = ('<p class="graphviz">\s*<img .*?/>\s*</p>\s*'
+            '<p class="caption"><span class="caption-text">caption of graph</span>')
+    assert re.search(html, content, re.S)