patman: Provide a way to intercept commands for testing

Add a test point for the command module. This allows tests to emulate
the execution of commands. This provides more control (since we can make
the fake 'commands' do whatever we like), makes it faster to write tests
since we don't need to set up as much environment, and speeds up test
execution.

Signed-off-by: Simon Glass <sjg@chromium.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/tools/patman/command.py b/tools/patman/command.py
index 7212fdfd40..d586f11158 100644
--- a/tools/patman/command.py
+++ b/tools/patman/command.py
@@ -20,9 +20,25 @@ class CommandResult:
     def __init__(self):
         self.stdout = None
         self.stderr = None
+        self.combined = None
         self.return_code = None
         self.exception = None
 
+    def __init__(self, stdout='', stderr='', combined='', return_code=0,
+                 exception=None):
+        self.stdout = stdout
+        self.stderr = stderr
+        self.combined = combined
+        self.return_code = return_code
+        self.exception = exception
+
+
+# This permits interception of RunPipe for test purposes. If it is set to
+# a function, then that function is called with the pipe list being
+# executed. Otherwise, it is assumed to be a CommandResult object, and is
+# returned as the result for every RunPipe() call.
+# When this value is None, commands are executed as normal.
+test_result = None
 
 def RunPipe(pipe_list, infile=None, outfile=None,
             capture=False, capture_stderr=False, oneline=False,
@@ -44,6 +60,10 @@ def RunPipe(pipe_list, infile=None, outfile=None,
     Returns:
         CommandResult object
     """
+    if test_result:
+        if hasattr(test_result, '__call__'):
+            return test_result(pipe_list=pipe_list)
+        return test_result
     result = CommandResult()
     last_pipe = None
     pipeline = list(pipe_list)