add graceful error handling for YAML import

Author: DannyBen

lib/bashly/refinements/compose_refinements.rb

@@ -6,7 +6,7 @@ def compose(keyword = 'import')
       result = {}
       each do |k, v|
         if k.to_s == keyword
-          sub = YAML.load_file(v).compose keyword
+          sub = safe_load_yaml(v).compose keyword
           if sub.is_a? Array
             result = sub
           else
@@ -20,6 +20,15 @@ def compose(keyword = 'import')
       end
       result
     end
+
+    def safe_load_yaml(path)
+      loaded = YAML.load_file path
+      return loaded if loaded.is_a? Array or loaded.is_a? Hash
+      raise Bashly::ConfigurationError, "Cannot find a valid YAML in '#{path}'"
+
+    rescue Errno::ENOENT
+      raise Bashly::ConfigurationError, "Cannot find import file '#{path}'"
+    end
   end
 
   refine Array do

spec/approvals/refinements/compose/error-invalid

@@ -0,0 +1 @@
+#<Bashly::ConfigurationError: Cannot find a valid YAML in 'examples/minimal/src/root_command.sh'>

spec/approvals/refinements/compose/error-not-found

@@ -0,0 +1 @@
+#<Bashly::ConfigurationError: Cannot find import file 'no-such-file.yml'>

spec/bashly/refinements/compose_refinements_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe ComposeRefinements, :focus do
+describe ComposeRefinements do
   using ComposeRefinements
 
   subject do
@@ -19,6 +19,22 @@
   describe '#compose' do
     it "calls #compose on all elements that respond to #compose" do
       expect(subject.compose.to_yaml).to match_approval "refinements/compose/array"
-    end    
+    end
+
+    context "when the import path does not exist" do
+      subject { { import: "no-such-file.yml" } }
+      
+      it "raises ConfigurationError" do
+        expect { subject.compose }.to raise_approval("refinements/compose/error-not-found")
+      end
+    end
+
+    context "when the import path does not contain a valid YAML front matter" do
+      subject { { import: "examples/minimal/src/root_command.sh" } }
+      
+      it "raises ConfigurationError" do
+        expect { subject.compose }.to raise_approval("refinements/compose/error-invalid")
+      end
+    end
   end
 end