diff --git a/.travis.yml b/.travis.yml
index 594565b46f0b..dca90b733a68 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -131,6 +131,7 @@ install:
         codecov \
         coverage \
         $CYCLER \
+        $DATEUTIL \
         $NOSE \
         $NUMPY \
         $PANDAS \
@@ -138,8 +139,8 @@ install:
         coverage \
         pillow \
         $PYPARSING \
-        $DATEUTIL \
-        $SPHINX
+        $SPHINX \
+        tornado
     # GUI toolkits are pip-installable only for some versions of Python so
     # don't fail if we can't install them.  Make it easier to check whether the
     # install was successful by trying to import the toolkit (sometimes, the
diff --git a/lib/matplotlib/tests/test_backends_interactive.py b/lib/matplotlib/tests/test_backends_interactive.py
index 1880a27af343..b66fe64e99b0 100644
--- a/lib/matplotlib/tests/test_backends_interactive.py
+++ b/lib/matplotlib/tests/test_backends_interactive.py
@@ -1,10 +1,15 @@
 import importlib
 import os
-from subprocess import Popen
+import signal
+import subprocess
 import sys
+import time
+import urllib.request
 
 import pytest
 
+import matplotlib as mpl
+
 
 # Minimal smoke-testing of the backends for which the dependencies are
 # PyPI-installable on Travis.  They are not available for all tested Python
@@ -17,6 +22,7 @@ def _get_testable_interactive_backends():
                           (["PyQt5"], "qt5agg"),
                           (["cairocffi", "PyQt5"], "qt5cairo"),
                           (["tkinter"], "tkagg"),
+                          (["wx"], "wx"),
                           (["wx"], "wxagg")]:
         reason = None
         if not os.environ.get("DISPLAY"):
@@ -30,20 +36,47 @@ def _get_testable_interactive_backends():
 
 _test_script = """\
 import sys
-from matplotlib import pyplot as plt
+from matplotlib import pyplot as plt, rcParams
+rcParams.update({
+    "webagg.open_in_browser": False,
+    "webagg.port_retries": 1,
+})
 
 fig = plt.figure()
 ax = fig.add_subplot(111)
-ax.plot([1,2,3], [1,3,1])
+ax.plot([1, 2], [2, 3])
 fig.canvas.mpl_connect("draw_event", lambda event: sys.exit())
 plt.show()
 """
+_test_timeout = 10  # Empirically, 1s is not enough on Travis.
 
 
 @pytest.mark.parametrize("backend", _get_testable_interactive_backends())
 @pytest.mark.flaky(reruns=3)
-def test_backend(backend):
-    proc = Popen([sys.executable, "-c", _test_script],
-                 env={**os.environ, "MPLBACKEND": backend})
-    # Empirically, 1s is not enough on Travis.
-    assert proc.wait(timeout=10) == 0
+def test_interactive_backend(backend):
+    subprocess.run([sys.executable, "-c", _test_script],
+                   env={**os.environ, "MPLBACKEND": backend},
+                   check=True,  # Throw on failure.
+                   timeout=_test_timeout)
+
+
+@pytest.mark.skipif(os.name == "nt", reason="Cannot send SIGINT on Windows.")
+def test_webagg():
+    pytest.importorskip("tornado")
+    proc = subprocess.Popen([sys.executable, "-c", _test_script],
+                            env={**os.environ, "MPLBACKEND": "webagg"})
+    url = "http://{}:{}".format(
+        mpl.rcParams["webagg.address"], mpl.rcParams["webagg.port"])
+    timeout = time.perf_counter() + _test_timeout
+    while True:
+        try:
+            conn = urllib.request.urlopen(url)
+            break
+        except urllib.error.URLError:
+            if time.perf_counter() > timeout:
+                pytest.fail("Failed to connect to the webagg server.")
+            else:
+                continue
+    conn.close()
+    proc.send_signal(signal.SIGINT)
+    assert proc.wait(timeout=_test_timeout) == 0