diff --git a/docs/custom_temp_file.rst b/docs/custom_temp_file.rst
new file mode 100644
index 0000000..653bb63
--- /dev/null
+++ b/docs/custom_temp_file.rst
@@ -0,0 +1,7 @@
+.. _custom_temp_file:
+
+Custom TempFile "Fixture
+========================
+
+.. automodule:: tests.custom_tmp_file
+   :members:
diff --git a/docs/multithreading_tests.rst b/docs/multithreading_tests.rst
index 87146fa..19a3729 100644
--- a/docs/multithreading_tests.rst
+++ b/docs/multithreading_tests.rst
@@ -4,3 +4,9 @@ Tests for the multithreading Module
 ===================================
 
 .. automodule:: tests.multithreading
+
+Tests for the multithreading.biomart Submodule
+----------------------------------------------
+
+.. automodule:: tests.multithreading.test_biomart
+   :members:
diff --git a/docs/testing.rst b/docs/testing.rst
index 22c1bc3..7a31681 100644
--- a/docs/testing.rst
+++ b/docs/testing.rst
@@ -4,7 +4,15 @@ Testing
 =======
 
 Each module within the source code has its own module for unit testing.
-Please see :ref:`logging_tests` and :ref:`multithreading_tests` for more information.
+Please see :ref:`logging_tests`,
+:ref:`data_handling_tests`,
+and :ref:`multithreading_tests` for more information.
+Additionally,
+there is a class-based "fixture" - 
+well it's not really a fixture,
+pytest doesn't allow class based fixtures - 
+for creating custom temporary file.
+Please see :ref:`custom_temp_file`.
 There are long term plans to develop integration tests for the whole pipeline.
 
 .. toctree::
@@ -14,3 +22,4 @@ There are long term plans to develop integration tests for the whole pipeline.
    logging_tests
    data_handling_tests
    multithreading_tests
+   custom_temp_file
diff --git a/environments/doc_build.txt b/environments/doc_build.txt
index c48a028..c05fe1d 100644
--- a/environments/doc_build.txt
+++ b/environments/doc_build.txt
@@ -3,4 +3,5 @@ docutils==0.16
 pandas==1.2.4
 bioservices==1.7.11
 lxml==4.6.3
+pytest==6.2.4
 sphinx-rtd-theme==0.5.2