Add Python code formatting with Black as Make steps

This patch adds two Make targets to the test environment so a manual
format-review can be done:

* Testing - `cd tests ; make check-black`
* Formatting - `cd tests ; make format`

Further discussion needs to be had before these are added to CI steps.

A follow-on patch will apply Black, so mechanical effects can be
separated from manual changes.

References:
* [AC-215] Evaluate pre-commit usage on casework repositories
* [AC-216] Apply Black to all casework Python code bases

Acked-by: kchason <kchason@users.noreply.github.com>
Signed-off-by: Alex Nelson <alexander.nelson@nist.gov>

Author: ajnelson-nist

tests/Makefile

@@ -67,6 +67,17 @@ check: \
 	    --ignore case_utils \
 	    --log-level=DEBUG
 
+# TODO - Need to settle on policy for incorporating this and 'format' recipe into CI.
+# https://case.atlassian.net/browse/AC-215
+# https://case.atlassian.net/browse/AC-216
+check-black: \
+  .venv.done.log
+	source venv/bin/activate \
+	  && black \
+	    --check \
+	    $(top_srcdir)/case_utils \
+	    $$PWD
+
 check-case_utils: \
   .venv.done.log
 	$(MAKE) \
@@ -101,3 +112,13 @@ clean:
 
 download: \
   .venv.done.log
+
+# TODO - Need to settle on policy for incorporating this and 'check-black' recipe into CI.
+# https://case.atlassian.net/browse/AC-215
+# https://case.atlassian.net/browse/AC-216
+format: \
+  .venv.done.log
+	source venv/bin/activate \
+	  && black \
+	    $(top_srcdir)/case_utils \
+	    $$PWD

tests/requirements.txt

@@ -1,4 +1,5 @@
 PyLD
+black
 mypy
 pytest
 python-dateutil