diff --git a/.travis.yml b/.travis.yml
index 286c55598..03f79179c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,12 +8,6 @@ dist: precise
 
 # TRAVIS_PYTHON_VERSION
 
-env:
-  global:
-    # This is necessary to have consistent testing of methods that rely on falling back to PATH for
-    # selecting a python interpreter.
-    - PATH=$PWD/.tox/py36/bin:$PWD/.tox/py27/bin:$PATH
-
 cache:
   directories:
     - .pyenv_test
diff --git a/tests/test_integration.py b/tests/test_integration.py
index 79ee5f975..abf9ef839 100644
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -343,17 +343,18 @@ def test_interpreter_constraints_to_pex_info_py2():
     assert set(['>=2.7', '<3']) == set(pex_info.interpreter_constraints)
 
 
-@pytest.mark.skip('https://github.com/pantsbuild/pex/issues/470')
 def test_interpreter_constraints_to_pex_info_py3():
-  with temporary_dir() as output_dir:
-    # target python 3
-    pex_out_path = os.path.join(output_dir, 'pex_py3.pex')
-    res = run_pex_command(['--disable-cache',
-      '--interpreter-constraint=>3',
-      '-o', pex_out_path])
-    res.assert_success()
-    pex_info = get_pex_info(pex_out_path)
-    assert ['>3'] == pex_info.interpreter_constraints
+  py3_interpreter = ensure_python_interpreter('3.6.3')
+  with environment_as(PATH=os.path.dirname(py3_interpreter)):
+    with temporary_dir() as output_dir:
+      # target python 3
+      pex_out_path = os.path.join(output_dir, 'pex_py3.pex')
+      res = run_pex_command(['--disable-cache',
+        '--interpreter-constraint=>3',
+        '-o', pex_out_path])
+      res.assert_success()
+      pex_info = get_pex_info(pex_out_path)
+      assert ['>3'] == pex_info.interpreter_constraints
 
 
 def test_interpreter_resolution_with_constraint_option():
@@ -497,61 +498,64 @@ def test_pex_exec_with_pex_python_path_and_pex_python_but_no_constraints():
     assert str(pex_python_path.split(':')[0]).encode() in stdout
 
 
-@pytest.mark.skip('https://github.com/pantsbuild/pex/issues/470')
 def test_pex_python():
-  with temporary_dir() as td:
-    pexrc_path = os.path.join(td, '.pexrc')
-    with open(pexrc_path, 'w') as pexrc:
-      pex_python = ensure_python_interpreter('3.6.3')
-      pexrc.write("PEX_PYTHON=%s" % pex_python)
-
-    # test PEX_PYTHON with valid constraints
-    pex_out_path = os.path.join(td, 'pex.pex')
-    res = run_pex_command(['--disable-cache',
-      '--rcfile=%s' % pexrc_path,
-      '--interpreter-constraint=>3',
-      '--interpreter-constraint=<3.8',
-      '-o', pex_out_path])
-    res.assert_success()
-
-    stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
-    stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
-    assert rc == 0
-    correct_interpreter_path = pex_python.encode()
-    assert correct_interpreter_path in stdout
-
-    # test PEX_PYTHON with incompatible constraints
-    pexrc_path = os.path.join(td, '.pexrc')
-    with open(pexrc_path, 'w') as pexrc:
-      pex_python = ensure_python_interpreter('2.7.10')
-      pexrc.write("PEX_PYTHON=%s" % pex_python)
-
-    pex_out_path = os.path.join(td, 'pex2.pex')
-    res = run_pex_command(['--disable-cache',
-      '--rcfile=%s' % pexrc_path,
-      '--interpreter-constraint=>3',
-      '--interpreter-constraint=<3.8',
-      '-o', pex_out_path])
-    res.assert_success()
-
-    stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
-    stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
-    assert rc == 1
-    fail_str = 'not compatible with specified interpreter constraints'.encode()
-    assert fail_str in stdout
-
-    # test PEX_PYTHON with no constraints
-    pex_out_path = os.path.join(td, 'pex3.pex')
-    res = run_pex_command(['--disable-cache',
-      '--rcfile=%s' % pexrc_path,
-      '-o', pex_out_path])
-    res.assert_success()
+  py2_path_interpreter = ensure_python_interpreter('2.7.10')
+  py3_path_interpreter = ensure_python_interpreter('3.6.3')
+  path = ':'.join([os.path.dirname(py2_path_interpreter), os.path.dirname(py3_path_interpreter)])
+  with environment_as(PATH=path):
+    with temporary_dir() as td:
+      pexrc_path = os.path.join(td, '.pexrc')
+      with open(pexrc_path, 'w') as pexrc:
+        pex_python = ensure_python_interpreter('3.6.3')
+        pexrc.write("PEX_PYTHON=%s" % pex_python)
+
+      # test PEX_PYTHON with valid constraints
+      pex_out_path = os.path.join(td, 'pex.pex')
+      res = run_pex_command(['--disable-cache',
+        '--rcfile=%s' % pexrc_path,
+        '--interpreter-constraint=>3',
+        '--interpreter-constraint=<3.8',
+        '-o', pex_out_path])
+      res.assert_success()
+
+      stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
+      stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
+      assert rc == 0
+      correct_interpreter_path = pex_python.encode()
+      assert correct_interpreter_path in stdout
 
-    stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
-    stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
-    assert rc == 0
-    correct_interpreter_path = pex_python.encode()
-    assert correct_interpreter_path in stdout
+      # test PEX_PYTHON with incompatible constraints
+      pexrc_path = os.path.join(td, '.pexrc')
+      with open(pexrc_path, 'w') as pexrc:
+        pex_python = ensure_python_interpreter('2.7.10')
+        pexrc.write("PEX_PYTHON=%s" % pex_python)
+
+      pex_out_path = os.path.join(td, 'pex2.pex')
+      res = run_pex_command(['--disable-cache',
+        '--rcfile=%s' % pexrc_path,
+        '--interpreter-constraint=>3',
+        '--interpreter-constraint=<3.8',
+        '-o', pex_out_path])
+      res.assert_success()
+
+      stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
+      stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
+      assert rc == 1
+      fail_str = 'not compatible with specified interpreter constraints'.encode()
+      assert fail_str in stdout
+
+      # test PEX_PYTHON with no constraints
+      pex_out_path = os.path.join(td, 'pex3.pex')
+      res = run_pex_command(['--disable-cache',
+        '--rcfile=%s' % pexrc_path,
+        '-o', pex_out_path])
+      res.assert_success()
+
+      stdin_payload = b'import sys; print(sys.executable); sys.exit(0)'
+      stdout, rc = run_simple_pex(pex_out_path, stdin=stdin_payload)
+      assert rc == 0
+      correct_interpreter_path = pex_python.encode()
+      assert correct_interpreter_path in stdout
 
 
 def test_entry_point_targeting():