Add Solutions#variable_names= to override automated variable name count.

Add `Solutions#==` and `Solutions`#eql?` to test solutions including variable names.

Author: gkellogg

lib/rdf/query/solution.rb

@@ -317,13 +317,12 @@ def to_h
     def hash
       @bindings.hash
     end
-    
+
     ##
     # Equivalence of solution
     def eql?(other)
       other.is_a?(Solution) && @bindings.eql?(other.bindings)
     end
-    alias_method :==, :eql?
 
     ##
     # Equals of solution

lib/rdf/query/solutions.rb

@@ -77,6 +77,15 @@ def variable_names
       end
     end
 
+    ##
+    # Sets variable names used in these solutions. If not set, the default is determined by the variables used in each solution.
+    #
+    # @param [Array<Symbol, RDF::Query::Variable>] vars
+    # @return [Array<Symbol>]
+    def variable_names=(vars)
+      @variable_names = vars.map(&:to_sym)
+    end
+
     ##
     # @overload variable?
     #   Returns `false`.
@@ -294,5 +303,17 @@ def limit(length)
       self
     end
     alias_method :limit!, :limit
+
+    ##
+    # Equivalence of solution
+    def eql?(other)
+      super && (!other.respond_to?(:variable_names) || variable_names.eql?(other.variable_names))
+    end
+
+    ##
+    # Equals of solution
+    def ==(other)
+      super && (!other.respond_to?(:variable_names) || variable_names.eql?(other.variable_names))
+    end
   end # Solutions
 end; end # RDF::Query

spec/query_solutions_spec.rb

@@ -305,6 +305,20 @@
     specify {is_expected.to include(:author, :age, :name, :description, :updated, :created, :title, :price, :date)}
   end
 
+  describe "#variable_names=" do
+    it "can set variable names from constants" do
+      solutions.variable_names = %i{author age foo}
+      expect(solutions.variable_names).to include(:author, :age, :foo)
+      expect(solutions.variable_names).not_to include(:name)
+    end
+
+    it "can set variable names from variables" do
+      solutions.variable_names = %w{author age foo}.map {|n| RDF::Query::Variable.new(n)}
+      expect(solutions.variable_names).to include(:author, :age, :foo)
+      expect(solutions.variable_names).not_to include(:name)
+    end
+  end
+
   describe "#count" do
     its(:count) {is_expected.to eq 2}
     it "Counting the number of matching solutions" do
@@ -318,6 +332,40 @@
     end
   end
 
+  describe "#eql?" do
+    it "is true for equivalent solutions" do
+      expect(solutions).to eql solutions.dup
+    end
+
+    it "is false for different solutions" do
+      solns2 = RDF::Query::Solutions(uri)
+      expect(solutions).not_to eql solns2
+    end
+
+    it "is false for the same solution with different variable_names" do
+      solns2 = solutions.dup
+      solns2.variable_names = %i{foo bar}
+      expect(solutions).not_to eql solns2
+    end
+  end
+
+  describe "#==" do
+    it "is true for equivalent solutions" do
+      expect(solutions).to eq solutions.dup
+    end
+
+    it "is false for different solutions" do
+      solns2 = RDF::Query::Solutions(uri)
+      expect(solutions).not_to eq solns2
+    end
+
+    it "is false for the same solution with different variable_names" do
+      solns2 = solutions.dup
+      solns2.variable_names = %i{foo bar}
+      expect(solutions).not_to eq solns2
+    end
+  end
+
   describe "#bindings" do
     subject {
       RDF::Query::Solutions(