Fix some errors on malformed license load

lib/code0/license/boundary.rb

@@ -20,7 +20,7 @@ def add_boundary(data, license_name)
 
         def remove_boundary(data)
           after_boundary = data.split(BOUNDARY_START).last
-          after_boundary.split(BOUNDARY_END).first
+          after_boundary&.split(BOUNDARY_END)&.first
         end
 
         private

lib/code0/license/encryptor.rb

@@ -42,6 +42,7 @@ def encrypt(data)
 
       def decrypt(data)
         raise KeyError, "Provided key is not a public key." unless key.public?
+        raise DecryptionError, "Provided data is nil" if data.nil?
 
         json_data = Base64.decode64(data.chomp)
 

spec/code0/license_spec.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 RSpec.describe Code0::License do
+  described_class.encryption_key = OpenSSL::PKey::RSA.generate(2048)
+
   let(:license_data) { default_license_data }
   let(:license) { described_class.new(license_data) }
   let(:default_license_data) do
@@ -31,6 +33,49 @@
     )
   end
 
+  describe ".load" do
+    subject(:load) { described_class.load(data) }
+
+    shared_examples "raises decryption error" do |example_name|
+      it(example_name) { expect { load }.to raise_error(Code0::License::Encryptor::DecryptionError) }
+    end
+
+    context "when data is nil" do
+      let(:data) { nil }
+
+      it { expect { load }.to raise_error(Code0::License::ValidationError) }
+    end
+
+    it_behaves_like "raises decryption error", "when data is an empty string" do
+      let(:data) { "" }
+    end
+
+    it_behaves_like "raises decryption error", "when data is a start boundary" do
+      let(:data) do
+        <<~DATA
+          --------BEGIN CODE0 LICENSE--------
+        DATA
+      end
+    end
+
+    it_behaves_like "raises decryption error", "when data is an end boundary" do
+      let(:data) do
+        <<~DATA
+          ---------END CODE0 LICENSE---------
+        DATA
+      end
+    end
+
+    it_behaves_like "raises decryption error", "when data is a boundary" do
+      let(:data) do
+        <<~DATA
+          --------BEGIN CODE0 LICENSE--------
+          ---------END CODE0 LICENSE---------
+        DATA
+      end
+    end
+  end
+
   describe "#valid?" do
     subject { license.valid? }