diff --git a/bin/compile b/bin/compile
index 556a828..ca2ebed 100755
--- a/bin/compile
+++ b/bin/compile
@@ -14,6 +14,10 @@ echo "Info: CACHE_DIR=$CACHE_DIR"
 if [ "$BUILDPACK_GHC_BASE_URL" != "" ]; then
   arch=$(uname -m)
   ghcver=$GHC_BOOTSTRAP_VERSION
+  if [ "$ghcver" == "" ]; then
+    echo "Error: please set GHC_BOOTSTRAP_VERSION";
+    exit 1;
+  fi;
   bsdir=$CACHE_DIR/bootstrap
   ghcurl="$BUILDPACK_GHC_BASE_URL/$ghcver/ghc-$ghcver-$arch-unknown-linux.tar.bz2"
   echo "Info: bootstrap directory: ${bsdir}";
diff --git a/features/compile.feature b/features/compile.feature
new file mode 100644
index 0000000..6bc7667
--- /dev/null
+++ b/features/compile.feature
@@ -0,0 +1,31 @@
+Feature: Compile
+
+  In order to build and deploy an application
+  As the bin/compile script of the buildpack
+  I want to download and bootstrap the environment
+
+  Scenario: BUILDPACK_GHC_BASE_URL not set
+    Given environment variable BUILDPACK_GHC_BASE_URL is set to ""
+    When I run `compile ../tmp/build ../tmp/cache`
+    Then the output should contain "Error: please set BUILDPACK_GHC_BASE_URL"
+    And  the exit status should be 1
+
+  Scenario: BUILDPACK_GHC_BASE_URL is set
+    Given environment variable BUILDPACK_GHC_BASE_URL is set to "http://www.haskell.org/ghc/dist"
+    When  I run `compile ../tmp/build ../tmp/cache`
+    Then  the output should not contain "Error: please set BUILDPACK_GHC_BASE_URL"
+    And   the exit status should be 0
+
+  Scenario: GHC_BOOTSTRAP_VERSION is not set
+    Given environment variable GHC_BOOTSTRAP_VERSION is set to ""
+    Given environment variable BUILDPACK_GHC_BASE_URL is set to "http://www.haskell.org/ghc/dist"
+    When  I run `compile ../tmp/build ../tmp/cache`
+    Then  the output should contain "Error: please set GHC_BOOTSTRAP_VERSION"
+    And   the exit status should be 1
+
+  Scenario: GHC_BOOTSTRAP_VERSION is set
+    Given environment variable GHC_BOOTSTRAP_VERSION is set to "7.0.4"
+    Given environment variable BUILDPACK_GHC_BASE_URL is set to "http://www.haskell.org/ghc/dist"
+    When  I run `compile ../tmp/build ../tmp/cache`
+    Then  the output should not contain "Error: please set GHC_BOOTSTRAP_VERSION"
+    And   the exit status should be 0
diff --git a/features/step_definitions/core.rb b/features/step_definitions/core.rb
index e69de29..fea857f 100644
--- a/features/step_definitions/core.rb
+++ b/features/step_definitions/core.rb
@@ -0,0 +1,5 @@
+
+Given /^environment variable (.*) is set to "([^"]*)"$/ do |name, value|
+  ENV[name]=value
+end
+