don't mock gem availablity function

Author: AbanoubGhadban

spec/react_on_rails/utils_spec.rb

@@ -34,12 +34,6 @@ module ReactOnRails
     end
 
     shared_context "with shakapacker enabled" do
-      before do
-        # Mock that shakapacker is not installed, so webpacker will be used instead
-        allow(described_class).to receive(:gem_available?).with("shakapacker").and_return(true)
-        allow(described_class).to receive(:gem_available?).with("webpacker").and_return(false)
-      end
-
       include_context "with packer enabled"
 
       # We don't need to mock anything here because the shakapacker gem is already installed and will be used by default
@@ -52,12 +46,6 @@ module ReactOnRails
     end
 
     shared_context "with webpacker enabled" do
-      before do
-        # Mock that shakapacker is not installed, so webpacker will be used instead
-        allow(described_class).to receive(:gem_available?).with("shakapacker").and_return(false)
-        allow(described_class).to receive(:gem_available?).with("webpacker").and_return(true)
-      end
-
       include_context "with packer enabled"
 
       it "uses webpacker" do