don't run coverage for pypy;

.travis/test.sh

@@ -5,9 +5,22 @@ export SITEPACKAGES=${SITEPACKAGES:-.}
 export PROJECT=venv_update
 NCPU=$(getconf _NPROCESSORS_CONF)
 
-coverage erase
-py.test -n $NCPU \
-    --cov --cov-config=$TOP/.coveragerc --cov-report='' \
-    "$@" $TOP/tests $SITEPACKAGES/${PROJECT}.py
-coverage combine
-coverage report --rcfile=$TOP/.coveragerc --fail-under 94  # FIXME: should be 100
+if python -c 'import platform; exit(not(platform.python_implementation() == "PyPy"))'; then
+    # coverage under pypy takes too dang long:
+    #   https://bitbucket.org/pypy/pypy/issue/1871/10x-slower-than-cpython-under-coverage#comment-14404182
+    PYPY=true
+else
+    PYPY=false
+fi
+
+if $PYPY; then
+    py.test -n $NCPU \
+        "$@" $TOP/tests $SITEPACKAGES/${PROJECT}.py
+else
+    coverage erase
+    py.test -n $NCPU \
+        --cov --cov-config=$TOP/.coveragerc --cov-report='' \
+        "$@" $TOP/tests $SITEPACKAGES/${PROJECT}.py
+    coverage combine
+    coverage report --rcfile=$TOP/.coveragerc --fail-under 94  # FIXME: should be 100
+fi