make psutil a dependency

Author: funbringer

Diff for: setup.py

@@ -6,7 +6,7 @@
     from distutils.core import setup
 
 # Basic dependencies
-install_requires = ["pg8000", "port-for>=0.4", "six>=1.9.0"]
+install_requires = ["pg8000", "port-for>=0.4", "six>=1.9.0", "psutil"]
 
 # Add compatibility enum class
 if sys.version_info < (3, 4):

Diff for: testgres/node.py

@@ -2,6 +2,7 @@
 
 import io
 import os
+import psutil
 import subprocess
 import time
 
@@ -183,11 +184,6 @@ def child_processes(self):
         Each process is represented by ProcessProxy object.
         """
 
-        try:
-            import psutil
-        except ImportError:
-            raise TestgresException("psutil module is not installed")
-
         # get a list of postmaster's children
         children = psutil.Process(self.pid).children()
 

Diff for: tests/test_simple.py

@@ -60,14 +60,6 @@ def good_properties(f):
             return True
 
 
-def module_exists(module):
-    try:
-        __import__(module)
-        return True
-    except ImportError:
-        return False
-
-
 @contextmanager
 def removing(f):
     try:
@@ -711,7 +703,6 @@ def test_version_management(self):
         self.assertTrue(b > c)
         self.assertTrue(a > c)
 
-    @unittest.skipUnless(module_exists('psutil'), 'might be missing')
     def test_child_pids(self):
         master_processes = [
             ProcessType.AutovacuumLauncher,