Further docs improvements

Author: varsill

lib/membrane/testing/pipeline.ex

@@ -14,30 +14,33 @@ defmodule Membrane.Testing.Pipeline do
   pass that options list to the `Membrane.Testing.Pipeline.start_link_supervised!/1`.
   The testing pipeline can be started in one of two modes - either with its `:default` behaviour, or by
   injecting a custom module behaviour. The usage of a `:default` pipeline implementation is presented below:
+  ```
+  spec = [
+      child(:el1, MembraneElement1)
+      |> child(:el2, MembraneElement2)
+      ...
+  ]
 
-    spec = [
-        child(:el1, MembraneElement1)
-        |> child(:el2, MembraneElement2)
-        ...
-    ]
-    options =  [
-      module: :default # :default is the default value for this parameter, so you do not need to pass it here
-      spec: spec
-    ]
-    pipeline = Membrane.Testing.Pipeline.start_link_supervised!(options)
+  options =  [
+    module: :default # :default is the default value for this parameter, so you do not need to pass it here
+    spec: spec
+  ]
 
+  pipeline = Membrane.Testing.Pipeline.start_link_supervised!(options)
+  ```
   You can also pass your custom pipeline's module as a `:module` option of
   the options list. Every callback of the module
   will be executed before the callbacks of Testing.Pipeline.
   Passed module has to return a proper spec. There should be no children
   nor links specified in options passed to test pipeline as that would
   result in a failure.
+  ```
+  options = [
+    module: Your.Module
+  ]
 
-    options = [
-      module: Your.Module
-    ]
-    pipeline = Membrane.Testing.Pipeline.start_link_supervised!(options)
-
+  pipeline = Membrane.Testing.Pipeline.start_link_supervised!(options)
+  ```
   See `t:Membrane.Testing.Pipeline.options/0` for available options.
 
   ## Assertions
@@ -53,15 +56,17 @@ defmodule Membrane.Testing.Pipeline do
   ## Example usage
 
   Firstly, we can start the pipeline providing its options as a keyword list:
+  ```
+  import Membrane.ChildrenSpec
 
-    import Membrane.ChildrenSpec
-    spec = [
-        child(:source, Membrane.Testing.Source)
-        |> child(:tested_element, TestedElement)
-        |> child(:sink, Membrane.Testing.Sink)
-    ]
-    {:ok, pipeline} = Membrane.Testing.Pipeline.start_link(spec: spec)
+  spec = [
+      child(:source, Membrane.Testing.Source)
+      |> child(:tested_element, TestedElement)
+      |> child(:sink, Membrane.Testing.Sink)
+  ]
 
+  {:ok, pipeline} = Membrane.Testing.Pipeline.start_link(spec: spec)
+  ```
   We can now wait till the end of the stream reaches the sink element (don't forget
   to import `Membrane.Testing.Assertions`):