Rewriting Client and changing interface

spec/yookassa_spec.rb

@@ -5,17 +5,40 @@ RSpec.describe Yookassa do
     expect(Yookassa::VERSION).not_to be nil
   end
 
-  describe ".configure" do
-    before do
-      Yookassa.configure do |config|
-        config.shop_id = 123
-        config.api_key = "test_321"
-      end
+  before do
+    Yookassa.configure do |config|
+      config.shop_id = 123
+      config.api_key = "test_321"
     end
+  end
 
+  describe ".configure" do
     it "stores settings and provides access to credentials" do
       expect(Yookassa.config.shop_id).to eq(123)
       expect(Yookassa.config.api_key).to eq("test_321")
     end
   end
+
+  describe ".client" do
+    context "when no settings are provided" do
+      before { Yookassa.instance_variable_set(:@config, nil) }
+
+      it "raises an error" do
+        expect { Yookassa.client }.to raise_error(Yookassa::ConfigError)
+      end
+    end
+
+    context "when instance configured" do
+      it "creates and stores client" do
+        expect(Yookassa.client).to be_a(Yookassa::Client)
+        expect(Yookassa.client).to eq(Yookassa.client)
+      end
+    end
+  end
+
+  describe ".payments" do
+    it "delegates request to client and creates an instance" do
+      expect(Yookassa.payments).to be_a(Yookassa::Payments)
+    end
+  end
 end