diff --git a/noxfile.py b/noxfile.py
index 2e6e889..e238c97 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -20,30 +20,6 @@
 
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 
-TEST_DEPENDENCIES = [
-    "flask",
-    "freezegun",
-    "mock",
-    "oauth2client",
-    "pyopenssl",
-    "pytest",
-    "pytest-cov",
-    "pytest-localserver",
-    "pyu2f",
-    "requests",
-    "urllib3",
-    "cryptography",
-    "responses",
-    "grpcio",
-]
-
-ASYNC_DEPENDENCIES = [
-    "pytest-asyncio",
-    "aioresponses",
-    "asynctest",
-    "aiohttp!=3.7.4.post0",
-]
-
 BLACK_VERSION = "black==19.3b0"
 BLACK_PATHS = [
     "google",
@@ -91,10 +67,8 @@
     constraints_path = str(
         CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
     )
-    add_constraints = ["-c", constraints_path]
-    session.install(*(TEST_DEPENDENCIES + add_constraints))
-    session.install(*(ASYNC_DEPENDENCIES + add_constraints))
-    session.install("-e", ".", *add_constraints)
+    session.install("-r", "testing/requirements.txt", "-c", constraints_path)
+    session.install("-e", ".", "-c", constraints_path)
     session.run(
         "pytest",
         f"--junitxml=unit_{session.python}_sponge_log.xml",
@@ -109,8 +83,7 @@
 
 @nox.session(python="3.7")
 def cover(session):
-    session.install(*TEST_DEPENDENCIES)
-    session.install(*(ASYNC_DEPENDENCIES))
+    session.install("-r", "testing/requirements.txt")
     session.install("-e", ".")
     session.run(
         "pytest",
@@ -128,7 +101,7 @@
 @nox.session(python="3.7")
 def docgen(session):
     session.env["SPHINX_APIDOC_OPTIONS"] = "members,inherited-members,show-inheritance"
-    session.install(*TEST_DEPENDENCIES)
+    session.install("-r", "testing/requirements.txt")
     session.install("sphinx")
     session.install("-e", ".")
     session.run("rm", "-r", "docs/reference")
@@ -168,8 +141,7 @@
 
 @nox.session(python="pypy")
 def pypy(session):
-    session.install(*TEST_DEPENDENCIES)
-    session.install(*ASYNC_DEPENDENCIES)
+    session.install("-r", "test/requirements.txt")
     session.install("-e", ".")
     session.run(
         "pytest",
diff --git a/system_tests/secrets.tar.enc b/system_tests/secrets.tar.enc
index 66c8ff4..646bb23 100644
--- a/system_tests/secrets.tar.enc
+++ b/system_tests/secrets.tar.enc
Binary files differ
diff --git a/testing/requirements.txt b/testing/requirements.txt
new file mode 100644
index 0000000..df20f96
--- /dev/null
+++ b/testing/requirements.txt
@@ -0,0 +1,20 @@
+# Unit test requirements
+flask
+freezegun
+mock
+oauth2client
+pyopenssl
+pytest
+pytest-cov
+pytest-localserver
+pyu2f
+requests
+urllib3
+cryptography
+responses
+grpcio
+# Async Dependencies
+pytest-asyncio; python_version > '3.0'
+aioresponses; python_version > '3.0'
+asynctest; python_version > '3.0'
+aiohttp; python_version > '3.0'
\ No newline at end of file