diff --git a/harness/constants.py b/harness/constants.py
index 874dec86b..38aae6fd3 100644
--- a/harness/constants.py
+++ b/harness/constants.py
@@ -1,26 +1,26 @@
 MAP_VERSION_TO_INSTALL_SKLEARN = {
     k: {
         "python": "3.6",
-        "packages": "numpy scipy cython pytest pandas matplotlib",
+        "packages": "numpy scipy Cython==0.27 pytest pandas matplotlib",
         "install": "pip install -v --no-use-pep517 --no-build-isolation -e .",
     }
-    for k in ["0.20", "0.21", "0.22"]
+    for k in ["0.20"]
 }
 MAP_VERSION_TO_INSTALL_SKLEARN.update(
     {
         k: {
             "python": "3.7",
-            "packages": "numpy scipy cython pytest pandas matplotlib",
+            "packages": "numpy scipy Cython==0.29 pytest pandas matplotlib",
             "install": "pip install -v --no-use-pep517 --no-build-isolation -e .",
         }
-        for k in ["0.23", "0.24"]
+        for k in ["0.21", "0.22", "0.23", "0.24"]
     }
 )
 MAP_VERSION_TO_INSTALL_SKLEARN.update(
     {
         k: {
             "python": "3.9",
-            "packages": "numpy scipy cython pytest pandas matplotlib joblib threadpoolctl",
+            "packages": "numpy scipy Cython==0.29 pytest pandas matplotlib joblib threadpoolctl",
             "install": "pip install -v --no-use-pep517 --no-build-isolation -e .",
         }
         for k in ["1.0", "1.1", "1.2", "1.3", "1.4"]
@@ -215,12 +215,25 @@
     ].append("sed -i 's/Jinja2>=2.3/Jinja2<3.1/' setup.py")
 
 MAP_VERSION_TO_INSTALL_ASTROPY = {
-    k: {"python": "3.9", "install": "pip install -e .[test]"}
-    for k in
-        ["0.1", "0.2", "0.3", "0.4", "1.1", "1.2", "1.3", "3.0", "3.1", "3.2"] + \
-        ["4.1", "4.2", "4.3", "5.0", "5.1", "5.2"]
+    k: {
+        "python": "3.9",
+        "install": "python setup.py install",
+        "pip_packages": "pytest extension-helpers numpy",
+    }
+    for k in ["0.1", "0.2", "0.3", "0.4", "1.1", "1.2", "1.3", "3.0", "3.1", "3.2"]
 }
 
+MAP_VERSION_TO_INSTALL_ASTROPY.update(
+    {
+        k: {
+            "python": "3.9",
+            "install": "pip install -e .[test]",
+            "pip_packages": "pytest extension-helpers numpy",
+        }
+        for k in ["4.1", "4.2", "4.3", "5.0", "5.1", "5.2"]
+    }
+)
+
 MAP_VERSION_TO_INSTALL_SYMPY = {
     k: {
         "python": "3.9",
diff --git a/harness/context_manager.py b/harness/context_manager.py
index ae5e804ff..073be5083 100644
--- a/harness/context_manager.py
+++ b/harness/context_manager.py
@@ -321,12 +321,23 @@ def __enter__(self):
                     os.remove(path_to_reqs)
                 else:
                     # Create environment + install dependencies
-                    cmd = f"{exec_cmd} create -n {env_name} python={install['python']} {pkgs} -y"
+                    cmd = f"{exec_cmd} create -n {env_name} python={install['python']} -y"
                     logger_testbed.info(
                         f"[Testbed] Creating environment {env_name}; Command: {cmd}"
                     )
                     self.exec(cmd.split(" "))
 
+                    # Activate the environment and install the packages
+                    activate_cmd = f". {path_activate} {env_name}"
+                    full_cmd = f"{activate_cmd} && echo 'activate successful'"
+                    if pkgs != "":
+                        install_cmd = f"pip install {pkgs}"
+                        full_cmd += f" && {install_cmd}"
+                    logger_testbed.info(
+                        f"[Testbed] Installing environment dependencies {pkgs}; Command: {full_cmd}"
+                    )
+                    self.exec(full_cmd, shell=True)
+
                 # Install additional packages if specified
                 if "pip_packages" in install:
                     cmd = f"source {path_activate} {env_name} && pip install {install['pip_packages']}"