doc: pytest: Document the test_bind test

Add this test to the documentation. None of the functions had comments,
so attempt to explain what each does.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/develop/pytest/index.rst

@@ -18,6 +18,7 @@ Individual tests
    :maxdepth: 1
 
    test_000_version
+   test_bind
    test_bootstage
    test_efi_loader
    test_net

doc/develop/pytest/test_bind.rst

@@ -0,0 +1,8 @@
+test_bind
+=========
+
+.. automodule:: test_bind
+   :synopsis:
+   :member-order: bysource
+   :members:
+   :undoc-members:

test/py/tests/test_bind.py

@@ -7,6 +7,7 @@ import re
 import pytest
 
 def in_tree(response, name, uclass, drv, depth, last_child):
+    """A helper function to confirm contents of the device tree """
     lines = [x.strip() for x in response.splitlines()]
     leaf = ''
     if depth != 0:
@@ -28,7 +29,12 @@ def in_tree(response, name, uclass, drv, depth, last_child):
 @pytest.mark.boardspec('sandbox')
 @pytest.mark.buildconfigspec('cmd_bind')
 def test_bind_unbind_with_node(ubman):
+    """Test the bind and unbind commands of a node
 
+    Verify that the dm tree output contains some expected nodes, and then bind
+    and unbind a USB via node device while verifying that the dm tree output
+    matches the expected values at each step.
+    """
     tree = ubman.run_command('dm tree')
     assert in_tree(tree, 'bind-test', 'simple_bus', 'simple_bus', 0, True)
     assert in_tree(tree, 'bind-test-child1', 'phy', 'phy_sandbox', 1, False)
@@ -106,6 +112,7 @@ def test_bind_unbind_with_node(ubman):
     assert response == ''
 
 def get_next_line(tree, name):
+    """A helper function to strip content out of dm tree output"""
     treelines = [x.strip() for x in tree.splitlines() if x.strip()]
     child_line = ''
     for idx, line in enumerate(treelines):
@@ -121,6 +128,11 @@ def get_next_line(tree, name):
 @pytest.mark.buildconfigspec('cmd_bind')
 @pytest.mark.singlethread
 def test_bind_unbind_with_uclass(ubman):
+    """Test the bind and unbind commands of a class
+
+    Bind and unbind the simple_bus class while verifying that the dm tree
+    output matches the expected values at each step.
+    """
     #bind /bind-test
     response = ubman.run_command('bind  /bind-test simple_bus')
     assert response == ''