test/py: use " for docstrings

Python's coding style docs indicate to use " not ' for docstrings.

test/py has other violations of the coding style docs, since the docs
specify a stranger style than I would expect, but nobody has complained
about those yet:-)

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_env.py b/test/py/tests/test_env.py
index 557c3af..651303f 100644
--- a/test/py/tests/test_env.py
+++ b/test/py/tests/test_env.py
@@ -10,34 +10,34 @@
 # FIXME: This might be useful for other tests;
 # perhaps refactor it into ConsoleBase or some other state object?
 class StateTestEnv(object):
-    '''Container that represents the state of all U-Boot environment variables.
+    """Container that represents the state of all U-Boot environment variables.
     This enables quick determination of existant/non-existant variable
     names.
-    '''
+    """
 
     def __init__(self, u_boot_console):
-        '''Initialize a new StateTestEnv object.
+        """Initialize a new StateTestEnv object.
 
         Args:
             u_boot_console: A U-Boot console.
 
         Returns:
             Nothing.
-        '''
+        """
 
         self.u_boot_console = u_boot_console
         self.get_env()
         self.set_var = self.get_non_existent_var()
 
     def get_env(self):
-        '''Read all current environment variables from U-Boot.
+        """Read all current environment variables from U-Boot.
 
         Args:
             None.
 
         Returns:
             Nothing.
-        '''
+        """
 
         response = self.u_boot_console.run_command('printenv')
         self.env = {}
@@ -48,27 +48,27 @@
             self.env[var] = value
 
     def get_existent_var(self):
-        '''Return the name of an environment variable that exists.
+        """Return the name of an environment variable that exists.
 
         Args:
             None.
 
         Returns:
             The name of an environment variable.
-        '''
+        """
 
         for var in self.env:
             return var
 
     def get_non_existent_var(self):
-        '''Return the name of an environment variable that does not exist.
+        """Return the name of an environment variable that does not exist.
 
         Args:
             None.
 
         Returns:
             The name of an environment variable.
-        '''
+        """
 
         n = 0
         while True:
@@ -80,7 +80,7 @@
 ste = None
 @pytest.fixture(scope='function')
 def state_test_env(u_boot_console):
-    '''pytest fixture to provide a StateTestEnv object to tests.'''
+    """pytest fixture to provide a StateTestEnv object to tests."""
 
     global ste
     if not ste:
@@ -88,7 +88,7 @@
     return ste
 
 def unset_var(state_test_env, var):
-    '''Unset an environment variable.
+    """Unset an environment variable.
 
     This both executes a U-Boot shell command and updates a StateTestEnv
     object.
@@ -99,14 +99,14 @@
 
     Returns:
         Nothing.
-    '''
+    """
 
     state_test_env.u_boot_console.run_command('setenv %s' % var)
     if var in state_test_env.env:
         del state_test_env.env[var]
 
 def set_var(state_test_env, var, value):
-    '''Set an environment variable.
+    """Set an environment variable.
 
     This both executes a U-Boot shell command and updates a StateTestEnv
     object.
@@ -118,26 +118,26 @@
 
     Returns:
         Nothing.
-    '''
+    """
 
     state_test_env.u_boot_console.run_command('setenv %s "%s"' % (var, value))
     state_test_env.env[var] = value
 
 def validate_empty(state_test_env, var):
-    '''Validate that a variable is not set, using U-Boot shell commands.
+    """Validate that a variable is not set, using U-Boot shell commands.
 
     Args:
         var: The variable name to test.
 
     Returns:
         Nothing.
-    '''
+    """
 
     response = state_test_env.u_boot_console.run_command('echo $%s' % var)
     assert response == ''
 
 def validate_set(state_test_env, var, value):
-    '''Validate that a variable is set, using U-Boot shell commands.
+    """Validate that a variable is set, using U-Boot shell commands.
 
     Args:
         var: The variable name to test.
@@ -145,7 +145,7 @@
 
     Returns:
         Nothing.
-    '''
+    """
 
     # echo does not preserve leading, internal, or trailing whitespace in the
     # value. printenv does, and hence allows more complete testing.
@@ -153,20 +153,20 @@
     assert response == ('%s=%s' % (var, value))
 
 def test_env_echo_exists(state_test_env):
-    '''Test echoing a variable that exists.'''
+    """Test echoing a variable that exists."""
 
     var = state_test_env.get_existent_var()
     value = state_test_env.env[var]
     validate_set(state_test_env, var, value)
 
 def test_env_echo_non_existent(state_test_env):
-    '''Test echoing a variable that doesn't exist.'''
+    """Test echoing a variable that doesn't exist."""
 
     var = state_test_env.set_var
     validate_empty(state_test_env, var)
 
 def test_env_printenv_non_existent(state_test_env):
-    '''Test printenv error message for non-existant variables.'''
+    """Test printenv error message for non-existant variables."""
 
     var = state_test_env.set_var
     c = state_test_env.u_boot_console
@@ -175,14 +175,14 @@
     assert(response == '## Error: "%s" not defined' % var)
 
 def test_env_unset_non_existent(state_test_env):
-    '''Test unsetting a nonexistent variable.'''
+    """Test unsetting a nonexistent variable."""
 
     var = state_test_env.get_non_existent_var()
     unset_var(state_test_env, var)
     validate_empty(state_test_env, var)
 
 def test_env_set_non_existent(state_test_env):
-    '''Test set a non-existant variable.'''
+    """Test set a non-existant variable."""
 
     var = state_test_env.set_var
     value = 'foo'
@@ -190,7 +190,7 @@
     validate_set(state_test_env, var, value)
 
 def test_env_set_existing(state_test_env):
-    '''Test setting an existant variable.'''
+    """Test setting an existant variable."""
 
     var = state_test_env.set_var
     value = 'bar'
@@ -198,14 +198,14 @@
     validate_set(state_test_env, var, value)
 
 def test_env_unset_existing(state_test_env):
-    '''Test unsetting a variable.'''
+    """Test unsetting a variable."""
 
     var = state_test_env.set_var
     unset_var(state_test_env, var)
     validate_empty(state_test_env, var)
 
 def test_env_expansion_spaces(state_test_env):
-    '''Test expanding a variable that contains a space in its value.'''
+    """Test expanding a variable that contains a space in its value."""
 
     var_space = None
     var_test = None