diff --git a/lib/spack/spack/test/build_environment.py b/lib/spack/spack/test/build_environment.py
index 281d79f8563..dd42d5cb458 100644
--- a/lib/spack/spack/test/build_environment.py
+++ b/lib/spack/spack/test/build_environment.py
@@ -15,6 +15,8 @@
 from llnl.util.filesystem import HeaderList, LibraryList
 
 import spack.build_environment
+import spack.compiler
+import spack.compilers
 import spack.config
 import spack.deptypes as dt
 import spack.package_base
diff --git a/lib/spack/spack/test/concretize_requirements.py b/lib/spack/spack/test/concretize_requirements.py
index be66b2b0a82..9e703be51fe 100644
--- a/lib/spack/spack/test/concretize_requirements.py
+++ b/lib/spack/spack/test/concretize_requirements.py
@@ -10,8 +10,10 @@
 import spack.config
 import spack.error
 import spack.package_base
+import spack.paths
 import spack.repo
 import spack.solver.asp
+import spack.store
 import spack.util.spack_yaml as syaml
 import spack.version
 from spack.installer import PackageInstaller
diff --git a/lib/spack/spack/test/flag_mixing.py b/lib/spack/spack/test/flag_mixing.py
index 6009ade058e..878c0c71efc 100644
--- a/lib/spack/spack/test/flag_mixing.py
+++ b/lib/spack/spack/test/flag_mixing.py
@@ -8,6 +8,7 @@
 
 import spack.config
 import spack.environment as ev
+import spack.paths
 import spack.repo
 import spack.util.spack_yaml as syaml
 from spack.spec import Spec