[IMPROVEMENT] Unittest for Mocking template_renderer

[Tarun-Arora]

Please prefix your pull request with one of the following: [FEATURE] [FIX] [IMPROVEMENT].

In raising this pull request, I confirm the following (please check boxes):

• I have read and understood the contributors guide.
• I have checked that another pull request for this purpose does not exist.
• I have considered, and confirmed that this submission will be valuable to others.
• I accept that this submission may not be used, and the pull request closed at the will of the maintainer.
• I give this submission freely, and claim no ownership to its content.

My familiarity with the project is as follows (check one):

• I have never used the project.
• I have used the project briefly.
• I have used the project extensively, but have not contributed previously.
• I am an active contributor to the project.

---

This Pull Request expects to fulfill the suggested improvement in #305.

[codecov]

Codecov Report

Merging #624 (0eceb68) into master (ba1c72b) will not change coverage.
The diff coverage is n/a.

❗ Current head 0eceb68 differs from pull request most recent head f35b32b. Consider uploading reports for the commit f35b32b to get more accurate results

@@           Coverage Diff           @@
##           master     #624   +/-   ##
=======================================
  Coverage   81.39%   81.39%           
=======================================
  Files          36       36           
  Lines        3606     3606           
  Branches      491      491           
=======================================
  Hits         2935     2935           
  Misses        535      535           
  Partials      136      136           

Flag	Coverage Δ
unittests	81.39% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ba1c72b...f35b32b. Read the comment docs.

[thealphadollar]

The changes look good to me.

However, I'm more interested in identifying how we can now use the method of mocking template_renderer to increase out tests coverage. This would require some investigation through the lines of code we are not testing right now.