Use python -m to run utilities on Travis

It's more reliable than just running the utility.

.travis.yml

@@ -68,7 +68,7 @@ matrix:
 before_install:
   # We hard-code the sphinx_rtd_theme to lock in our build with patch for
   # version chooser
-  - pip install --upgrade pip;
+  - python -m pip install --upgrade pip;
   - if [[ ! -f $HOME/local/lib/libproj.so ]]; then
         wget http://download.osgeo.org/proj/proj-4.9.3.tar.gz;
         tar xf proj-4.9.3.tar.gz;
@@ -97,18 +97,18 @@ before_install:
     fi;
   - mkdir $WHEELDIR;
   # These need to be downloaded because when we run builds later we disable the index
-  - pip download -d $WHEELDIR -f $WHEELHOUSE setuptools wheel setuptools_scm;
+  - python -m pip download -d $WHEELDIR -f $WHEELHOUSE setuptools wheel setuptools_scm;
   # Cython needs to be installed before even downloading CartoPy
-  - pip install Cython;
-  - pip download -d $WHEELDIR ".[$EXTRA_INSTALLS]" $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
+  - python -m pip install Cython;
+  - python -m pip download -d $WHEELDIR ".[$EXTRA_INSTALLS]" $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
   - touch $WHEELDIR/download_marker && ls -lrt $WHEELDIR;
-  - travis_wait pip wheel -w $WHEELDIR $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
-  - pip install $EXTRA_PACKAGES --upgrade --upgrade-strategy=eager --no-index -f file://$PWD/$WHEELDIR $VERSIONS;
-  - travis_wait 30 pip wheel -w $WHEELDIR ".[$EXTRA_INSTALLS]" $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
+  - travis_wait python -m pip wheel -w $WHEELDIR $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
+  - python -m pip install $EXTRA_PACKAGES --upgrade --upgrade-strategy=eager --no-index -f file://$PWD/$WHEELDIR $VERSIONS;
+  - travis_wait 30 python -m pip wheel -w $WHEELDIR ".[$EXTRA_INSTALLS]" $EXTRA_PACKAGES -f $WHEELHOUSE $PRE $VERSIONS;
   - rm -f $WHEELDIR/MetPy*.whl;
 
 install:
-  - pip install ".[$EXTRA_INSTALLS]" --upgrade --upgrade-strategy=eager --no-index $PRE -f file://$PWD/$WHEELDIR $VERSIONS;
+  - python -m pip install ".[$EXTRA_INSTALLS]" --upgrade --upgrade-strategy=eager --no-index $PRE -f file://$PWD/$WHEELDIR $VERSIONS;
 
 script:
   - if [[ $TASK == "docs" ]]; then
@@ -129,7 +129,7 @@ script:
       fi;
     else
       flake8 --version;
-      pytest $TEST_OUTPUT_CONTROL $TEST_OPTS;
+      python -m pytest $TEST_OUTPUT_CONTROL $TEST_OPTS;
     fi
 
 after_script: