Improved inputs documentation

- Added Computable Inputs to docs
- Added small section about input manipulation (add/remove)

Change-Id: I299af52abad347ed29a140f59adedb78f15485e6

doc/source/resource.rst

@@ -93,6 +93,45 @@ all values are correct. ``!`` at the end of a type means that it is required
   * list with lists ``[[]]``
 
 
+Input manipulation
+~~~~~~~~~~~~~~~~~~
+There is possibility to add and remove inputs from given resource.
+To do so you can use ``solar input add`` or ``solar input remove`` in Solar CLI.
+
+
+Computable Inputs
+-----------------
+Computable input is special input type, it shares all logic that standard input has (connections etc),
+but you can set a function that will return final input value.
+
+.. note::
+   Remeber, that you need to connect inputs to have it accessible in Computable Inputs logic.
+
+Currently you can write the functions using:
+
+- Pure Python
+- Jinja2 template
+- LUA
+
+Besides that there are 2 types of Computable Inputs:
+
+- ``values``
+
+  - all connected inputs are passed by value as ``D`` variable
+
+- ``full``
+
+  - all connected inputs are passed as array (python dict type) as ``R`` variable, so you have full information about input.
+
+
+In addition for ``jinja`` all connected inputs for current resource are accessible as first level variables.
+
+
+Change computable input
+~~~~~~~~~~~~~~~~~~~~~~~
+You can change Computable Input properties by calling ``solar input change_computable`` in Solar CLI.
+
+
 Action
 ------
 Solar wraps deployment code into actions with specific names. Actions are

solar/test/test_resource.py

@@ -162,6 +162,7 @@ input:
         """)
 
         sample1 = self.create_resource('sample1', sample_meta_dir)
+
         with self.assertRaises(Exception):  # NOQA
             sample1.input_computable_change('value', '{{value}}')
         return sample1