J2 test docs (#16646)

* moved tests from filters to actual jinja2 tests

also removed some unused declarations and imports

* split tests into their own docs

removed isnan as existing jinja2's 'number' already covers same
added missing docs for several tests

* updated as per feedback

lib/ansible/plugins/test/core.py

@@ -20,6 +20,9 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 import re
+import operator as py_operator
+from distutils.version import LooseVersion, StrictVersion
+
 from ansible import errors
 
 def failed(*a, **kw):
@@ -84,6 +87,33 @@ def search(value, pattern='', ignorecase=False, multiline=False):
     ''' Perform a `re.search` returning a boolean '''
     return regex(value, pattern, ignorecase, multiline, 'search')
 
+def version_compare(value, version, operator='eq', strict=False):
+    ''' Perform a version comparison on a value '''
+    op_map = {
+        '==': 'eq', '=':  'eq', 'eq': 'eq',
+        '<':  'lt', 'lt': 'lt',
+        '<=': 'le', 'le': 'le',
+        '>':  'gt', 'gt': 'gt',
+        '>=': 'ge', 'ge': 'ge',
+        '!=': 'ne', '<>': 'ne', 'ne': 'ne'
+    }
+
+    if strict:
+        Version = StrictVersion
+    else:
+        Version = LooseVersion
+
+    if operator in op_map:
+        operator = op_map[operator]
+    else:
+        raise errors.AnsibleFilterError('Invalid operator type')
+
+    try:
+        method = getattr(py_operator, operator)
+        return method(Version(str(value)), Version(str(version)))
+    except Exception as e:
+        raise errors.AnsibleFilterError('Version comparison: %s' % e)
+
 class TestModule(object):
     ''' Ansible core jinja2 tests '''
 
@@ -108,4 +138,7 @@ class TestModule(object):
             'search': search,
             'regex': regex,
 
+            # version comparison
+            'version_compare': version_compare,
+
         }