diff --git a/Makefile b/Makefile
index d43feb880..0d99cca91 100644
--- a/Makefile
+++ b/Makefile
@@ -3,8 +3,8 @@ init:
 
 test:
 	# Run unit tests
-	# Fail if coverage falls below 90%
-	LAMBDA_BUILDERS_DEV=1 pytest --cov aws_lambda_builders --cov-report term-missing --cov-fail-under 90 tests/unit tests/functional
+	# Fail if coverage falls below 94%
+	LAMBDA_BUILDERS_DEV=1 pytest --cov aws_lambda_builders --cov-report term-missing --cov-fail-under 94 tests/unit tests/functional
 
 func-test:
 	LAMBDA_BUILDERS_DEV=1 pytest tests/functional
diff --git a/aws_lambda_builders/workflows/python_pip/workflow.py b/aws_lambda_builders/workflows/python_pip/workflow.py
index f5af20ce9..fb2582b0d 100644
--- a/aws_lambda_builders/workflows/python_pip/workflow.py
+++ b/aws_lambda_builders/workflows/python_pip/workflow.py
@@ -18,7 +18,10 @@ class PythonPipWorkflow(BaseWorkflow):
 
     # Common source files to exclude from build artifacts output
     # Trimmed version of https://github.com/github/gitignore/blob/master/Python.gitignore
-    EXCLUDED_FILES = (".git",
+    EXCLUDED_FILES = (
+                      ".aws-sam", ".chalice",
+
+                      ".git",
 
                       # Compiled files
                       "*.pyc", "__pycache__", "*.so",
diff --git a/tests/functional/test_utils.py b/tests/functional/test_utils.py
new file mode 100644
index 000000000..69dcd3390
--- /dev/null
+++ b/tests/functional/test_utils.py
@@ -0,0 +1,50 @@
+import os
+import tempfile
+import shutil
+
+from unittest import TestCase
+
+from aws_lambda_builders.utils import copytree
+
+class TestCopyTree(TestCase):
+
+    def setUp(self):
+        self.source = tempfile.mkdtemp()
+        self.dest = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.source)
+        shutil.rmtree(self.dest)
+
+    def test_must_copy_files_recursively(self):
+        file(self.source, "a", "file.txt")
+        file(self.source, "a", "b", "file.txt")
+        file(self.source, "a", "c", "file.txt")
+
+        copytree(self.source, self.dest)
+        self.assertTrue(os.path.exists(os.path.join(self.dest, "a", "file.txt")))
+        self.assertTrue(os.path.exists(os.path.join(self.dest, "a", "b", "file.txt")))
+        self.assertTrue(os.path.exists(os.path.join(self.dest, "a", "c", "file.txt")))
+
+    def test_must_respect_excludes_list(self):
+        file(self.source, ".git", "file.txt")
+        file(self.source, "nested", ".aws-sam", "file.txt")
+        file(self.source, "main.pyc")
+        file(self.source, "a", "c", "file.txt")
+
+        excludes = [".git", ".aws-sam", "*.pyc"]
+
+        copytree(self.source, self.dest, ignore=shutil.ignore_patterns(*excludes))
+        self.assertEquals(set(os.listdir(self.dest)), {"nested", "a"})
+        self.assertEquals(set(os.listdir(os.path.join(self.dest, "nested"))), set())
+        self.assertEquals(set(os.listdir(os.path.join(self.dest, "a"))), {"c"})
+        self.assertEquals(set(os.listdir(os.path.join(self.dest, "a"))), {"c"})
+
+def file(*args):
+    path = os.path.join(*args)
+    basedir = os.path.dirname(path)
+    if not os.path.exists(basedir):
+        os.makedirs(basedir)
+
+    # empty file
+    open(path, 'a').close()