Expand connection pool error handling specs

spec/lib/mysql_framework/connector_spec.rb

@@ -426,17 +426,22 @@
     end
   end
 
-  describe 'connection pool error handling' do
+  describe 'when connection pool is exhausted' do
     before do
-      expect(subject).to_not receive(:check_in)
+      max_pool_size.times { subject.check_out }
     end
 
-    it 'does not add nil to the pool when full and an attempt is made to use it' do
-      conns = max_pool_size.times.map { subject.check_out }
-      expect { subject.query('select 1') }.to raise_error(RuntimeError)
-      # Previous versions had a bug where a nil would be added to the pool
-      # at this point.
-      expect { subject.connections.pop(true) } .to raise_error(ThreadError)
+    it 'pop throws exception' do
+      expect { subject.connections.pop(true) }.to raise_error(ThreadError)
+    end
+
+    it 'throws exception on query' do
+      expect { subject.query('SELECT 1') }.to raise_error(RuntimeError, /depleted/)
+    end
+
+    it 'does not put nil in the pool on error' do
+      expect(subject).to_not receive(:check_in).with(nil)
+      expect { subject.query('SELECT 1') }.to raise_error(RuntimeError, /depleted/)
     end
   end
 end