insist
An easy-to-use assertion library for python.
Quick Start
Install insist
$ pip install insist
or
$ sudo pip install insist
Create Insist object
from insist import Insist
insist = Insist()
# Raise RuntimeError instead of AssertionError
insist_rt = Insist(RuntimeError)
# Prefix all messages with "OOPS : "
insist_prefix = Insist(message_prefix="OOPS")
# Show both custom and standard error messages
# Can be combined with message_prefix
insist_both = Insist(always_show_standard=True)
Make assertions
insist.true(1 == 1) # Valid assertion
insist(1 == 1) # Same as insist.true(expr)
insist(1 == 2) # Raises AssertionError
# Raises AssertionError with custom error message
insist(1 == 2, "Danger, Will Robinson")
# Raises AssertionError with custom and standard error message joined with " : "
insist_both(1 == 2, "Danger, Will Robinson")
Reference
All tests
from insist import Insist
insist = Insist()
insist(x) # x == True
insist.true(x) # x == True
insist.false(x) # x == False
insist.always(custom) # Always raise an error
insist.equal(x, y) # x == y
insist.not_equal(x, y) # x != y
insist.less(x, y) # x < y
insist.less_equal(x, y) # x <= y
insist.greater(x, y) # x > y
insist.greater_equal(x, y) # x >= y
insist.is_same(x, y) # x is y
insist.is_not(x, y) # x is not y
insist.is_in(x, y) # x in y
insist.not_in(x, y) # x not in y
insist.is_subclass(x, y) # issubclass(x, y)
insist.is_not_subclass(x, y) # not issubclass(x, y)
insist.isa(x, y) # isinstance(x, y)
insist.is_not_a(x, y) # not isinstance(x, y)
insist.is_string(x, y) # isinstance(x, str) for Py3
# isinstance(x, (str, unicode)) for Py2
insist.is_not_string(x, y) # not isinstance(x, str) for Py3
# not isinstance(x, (str, unicode)) for Py2
insist.keys(x, required, optional, extra, custom) # See examples below
# Dict used for remaining examples
x = { 'a' : 1, 'b' : 2, 'c' : 3 }
# Require that x has listed keys with additional keys allowed.
insist.keys(x, required=['a', 'b']) # OK
insist.keys(x, required=['a', 'd']) # Raises error
# Require that x has listed keys with additional keys not allowed.
insist.keys(x, required=['a', 'b'], extra=False) # Raises error
# Require that x has listed keys but no keys other than optional keys allowed.
insist.keys(x, required=['a', 'b'], optional=['c']) # OK
insist.keys(x, required=['a', 'b'], optional=['d']) # Raises error
Chainable Tests
The "that" method retains its value and uses it as the first value for the remaining methods in chain. This simplifies the testing of a single value against multiple criteria.
from insist import Insist
insist = Insist()
x = 3
insist.that(x).isa(int).greater_equal(0).less(10) # OK if x is integer from 0 to 9
# The result of the "that" method may be stored in a variable as well.
say_x = insist.that(x)
say_x.isa(int).greater_equal(0)
say_x.less(len(message))
# In addition to the methods listed above, a "that chain" has two additional methods.
# The has and not_has methods are similar to is_in and not_in except that the
# arguments are reversed.
x = [ 1, 2, 3 ]
say_x = insist.that(x)
say_x.has(1).has(2) # OK
say_x.has(1).not_has(2) # Raises error
say_x.has(1).has(5) # Raises error
x = { 'a' : 1, 'b' : 2, 'c' : 3 }
say_x = insist.that(x)
say_x.has('a').has('b') # OK
say_x.has('a').has('d') # Raises error
Copyright and License
Copyright 2014 Ray Harris
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this module except in compliance with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.