TestFlows.com Open-Source Software Testing Framework Stash

Why

Allows to stash values or files that are generated during test program execution that could be reused on the next test program run.

Usage

Use stashed context manager to stash a value. If the value identified by name is found inside the stash then the code within the with block is not executed.

Example

Here is an example how to use testflows.stash module and the stashed context manager to stash a value returned by a function that takes a non trivial time to execute.

example1.py

import time
from testflows.stash import stashed

def generate_value():
    print("Generating a value that takes a long time...")
    time.sleep(10)
    return "my generated value"

with stashed("value") as stash:
   stash(generate_value())

print(stash.value)

In this example, we simulate the work done by the function using time.sleep(10). The stashed value is identified by the name argument passed when creating an instance of the stash using the stashed() context manager.

On the first run, when the value is not in a stash the code within the with block is executed where the value to be stashed is added by calling stash instance with the value to be stashed. In this case, the result of the generated_value() function.

$ python3 example1.py
Generating a value that takes a long time...
my generated value

Note that stash folder will be created in the same directory as the source file.

$ find
./stash
./stash/example1.py.stash
./example1.py

The stash folder will contain a file that stores the stashed value by using the name specified upon creation of the stash instance. The name of the stash file will have the same prefix as the original source file.

The content of the file will have the following

$ cat ./stash/example1.py.stash 
value = '"my generated value"'

On the second run, the value is found in a stash and the body of the with block is skipped and the generated_value() is not called and the stashed value is available using the stash.value where stash is the instance of the stashed() context manager.

$ python3 example1.py
my generated value

stashed()

The stashed context manager can take the following arguments.

stashed(name, id=None, output=None, path="./stash", encoder=json, use_stash=True)

where

• name name of the stashed value inside the stash file
• id custom stash id, default: None
• output function to output the representation of the value, default: None
• path custom stash folder path, default: ./stash
• encoder custom encoder for the value, default: json
• use_stash use stash, default: True. If False, then the stash will not be used and the with block is always executed regardless if the value is already stored in a stash

In general, stash file name format is defined as

<source file name>.<id>.stash