1 files changed, 59 insertions, 0 deletions
diff --git a/spec/support/graphql/var.rb b/spec/support/graphql/var.rb
new file mode 100644
index 00000000000..4f2c774e898
--- /dev/null
+++ b/spec/support/graphql/var.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module Graphql
+  # Helper to pass variables around generated queries.
+  #
+  # e.g.:
+  #   first = var('Int')
+  #   after = var('String')
+  #
+  #   query = with_signature(
+  #     [first, after],
+  #     query_graphql_path([
+  #       [:project, { full_path: project.full_path }],
+  #       [:issues, { after: after, first: first }]
+  #       :nodes
+  #     ], all_graphql_fields_for('Issue'))
+  #   )
+  #
+  #   post_graphql(query, variables: [first.with(2), after.with(some_cursor)])
+  #
+  class Var
+    attr_reader :name, :type
+    attr_accessor :value
+
+    def initialize(name, type)
+      @name = name
+      @type = type
+    end
+
+    def sig
+      "#{to_graphql_value}: #{type}"
+    end
+
+    def to_graphql_value
+      "$#{name}"
+    end
+
+    # We return a new object so that running the same query twice with
+    # different values does not risk re-using the value
+    #
+    # e.g.
+    #
+    #   x = var('Int')
+    #   expect { post_graphql(query, variables: x) }
+    #     .to issue_same_number_of_queries_as { post_graphql(query, variables: x.with(1)) }
+    #
+    # Here we post the `x` variable once with the value set to 1, and once with
+    # the value set to `nil`.
+    def with(value)
+      copy = Var.new(name, type)
+      copy.value = value
+      copy
+    end
+
+    def to_h
+      { name => value }
+    end
+  end
+end