Address feedback, add tests

spec/ameba/ast/variabling/type_def_variable_spec.cr

@@ -0,0 +1,30 @@
+require "../../../spec_helper"
+
+module Ameba::AST
+  describe TypeDecVariable do
+    var = Crystal::Var.new("foo")
+    declared_type = Crystal::Path.new("String")
+    type_dec = Crystal::TypeDeclaration.new(var, declared_type)
+
+    describe "#initialize" do
+      it "creates a new type dec variable" do
+        variable = TypeDecVariable.new(type_dec)
+        variable.node.should_not be_nil
+      end
+    end
+
+    describe "#name" do
+      it "returns var name" do
+        variable = TypeDecVariable.new(type_dec)
+        variable.name.should eq var.name
+      end
+
+      it "raises if type declaration is incorrect" do
+        type_dec = Crystal::TypeDeclaration.new(declared_type, declared_type)
+        expect_raises(Exception, "unsupported var node type: Crystal::Path") do
+          TypeDecVariable.new(type_dec).name
+        end
+      end
+    end
+  end
+end