add some query-builder tests

graphql-relay-walker.gemspec

@@ -11,6 +11,7 @@ Gem::Specification.new do |s|
 
   s.add_dependency "graphql", "~> 0.19"
 
-  s.add_development_dependency "rake",  "~> 11.3"
-  s.add_development_dependency "rspec", "~> 3.5"
+  s.add_development_dependency "rake",           "~> 11.3"
+  s.add_development_dependency "rspec",          "~> 3.5"
+  s.add_development_dependency "graphql-client", "~> 0.2"
 end

spec/fixtures/swapi_query.graphql

@@ -0,0 +1,137 @@
+query($id: ID!) {
+  node(id: $id) {
+    ... on Film {
+      speciesConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      starshipConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      vehicleConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      characterConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      planetConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+    ... on Person {
+      homeworld {
+        id
+      }
+      filmConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      species {
+        id
+      }
+      starshipConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      vehicleConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+    ... on Planet {
+      residentConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      filmConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+    ... on Species {
+      homeworld {
+        id
+      }
+      personConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      filmConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+    ... on Starship {
+      pilotConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      filmConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+    ... on Vehicle {
+      pilotConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+      filmConnection(first: 5) {
+        edges {
+          node {
+            id
+          }
+        }
+      }
+    }
+  }
+}

spec/query_builder_spec.rb

@@ -1,4 +1,58 @@
 require "graphql/relay/walker"
+require "graphql/client"
 
 describe GraphQL::Relay::Walker::QueryBuilder do
+  let(:schema_path)    { "spec/fixtures/swapi_schema.json" }
+  let(:query_path)     { "spec/fixtures/swapi_query.graphql" }
+  let(:schema)         { GraphQL::Client.load_schema(schema_path) }
+  let(:client)         { GraphQL::Client.new(schema: schema) }
+  let(:query_builder)  { described_class.new(schema) }
+  let(:ast)            { query_builder.ast }
+  let(:query_string)   { query_builder.query_string  }
+
+  describe "ast" do
+    subject { ast }
+
+    it "adds an alias to all fields except id and node" do
+      fields(ast).reject do |node|
+        %w(node id).include?(node.name)
+      end.each do |field|
+        expect(field.alias).not_to be_nil
+      end
+    end
+  end
+
+  describe "query_string" do
+    subject { query_string }
+
+    it "generates a valid query for the schema" do
+      expect { client.parse(query_string) }.not_to raise_error
+    end
+
+    describe "with aliases removed" do
+      before do
+        fields(ast).each { |field| field.alias = nil }
+      end
+
+      it "matches the expected query string" do
+        expect(subject).to eq(File.read(query_path).strip)
+      end
+    end
+  end
+
+  def fields(ast)
+    nodes(ast).select { |node| node.is_a?(GraphQL::Language::Nodes::Field) }
+  end
+
+  def nodes(ast)
+    children = if ast.respond_to?(:selections)
+      ast.selections
+    elsif ast.respond_to?(:definitions)
+      ast.definitions
+    else
+      []
+    end
+
+    children + children.map { |child| nodes(child) }.flatten
+  end
 end