Graph.generate: actually run the damn command.

lib/simplerrd/graph.rb

@@ -51,6 +51,20 @@ def format=(f)
       end
     end
 
+    def add_element(elt)
+      raise "Expected a Command; got " + elt.class.to_s unless elt.is_a?(Command)
+      @elements << elt
+    end
+
+    def dependencies
+      deps = []
+      @elements.each do |elt|
+        deps.concat(elt.all_dependencies)
+        deps << elt
+      end
+      return deps.uniq
+    end
+
     def command_flags
       flags = []
       flags.concat(['--start', @start.to_i.to_s]) if @start
@@ -65,5 +79,20 @@ def command_flags
       flags.concat(['--imgformat', @format]) if @format
       return flags
     end
+
+    def command_expressions
+      exprs = []
+      dependencies.each do |dep|
+        exprs << dep.definition
+      end
+      return exprs
+    end
+
+    def generate(filename = '-')
+      cmd = ['rrdtool', 'graph', filename]
+      cmd.concat(command_flags)
+      cmd.concat(command_expressions)
+      Runner.run(*cmd)
+    end
   end
 end

spec/graph_spec.rb

@@ -44,6 +44,28 @@
     lambda { @g.format = "bread" }.should raise_error
   end
 
+  it "should (only) allow adding RPN Commands to the graph" do
+    d = SimpleRRD::Def.new
+    @g.add_element(d)
+    @g.elements.should include(d)
+    lambda { @g.add_element(123) }.should raise_error
+  end
+
+  it "should return all dependencies in #dependenceies" do
+    d = SimpleRRD::Line.new
+    e = SimpleRRD::Area.new
+    @g.add_element(d)
+    @g.add_element(e)
+    d.should_receive(:all_dependencies).and_return([:foo,:bar])
+    e.should_receive(:all_dependencies).and_return([:foo,:baz])
+    deps = @g.dependencies
+    deps.should include(:foo)
+    deps.should include(:bar)
+    deps.should include(:baz)
+    deps.should include(d)
+    deps.should include(e)
+  end
+
   it "should generate appropriate commandline flags for the options set" do
     e = Time.now
     s = e - 3600
@@ -67,9 +89,53 @@
     @g.command_flags.should == ['--end', 'now']
   end
 
-  it "should allow setting the various options through the constructor hash" do
-    n = SimpleRRD::Graph.new(:title => "TITLE", :width => 100)
-    n.title.should == "TITLE"
-    n.width.should == 100
+  it "#command_expressions should return the definition of all of the graph's dependencies" do
+    a = SimpleRRD::Def.new
+    a.should_receive(:definition).and_return('DEF:blah:bloo')
+
+    d = SimpleRRD::Line.new
+    d.should_receive(:dependencies).and_return([a])
+    d.should_receive(:definition).and_return('LINE:foo:bar')
+
+    @g.add_element(d)
+
+    exprs = @g.command_expressions
+    exprs.should include('DEF:blah:bloo')
+    exprs.should include('LINE:foo:bar')
+  end
+
+  it "should use Runner.run to execute the proper command" do
+    e = Time.now
+    s = e - 3600
+
+    @g.start = s
+    @g.end = e
+    @g.title = "MY GRAF"
+    @g.width = 640
+    @g.height = 480
+    @g.format = "PNG"
+
+    a = SimpleRRD::Def.new
+    a.should_receive(:definition).and_return('DEF:blah:bloo')
+
+    d = SimpleRRD::Line.new
+    d.should_receive(:dependencies).and_return([a])
+    d.should_receive(:definition).and_return('LINE:foo:bar')
+
+    @g.add_element(d)
+
+    expected_command = ['rrdtool', 'graph', '-',
+                        '--start', s.to_i.to_s,
+                        '--end',   e.to_i.to_s,
+                        '--title', "MY GRAF",
+                        '--width', '640',
+                        '--height', '480',
+                        '--imgformat', 'PNG',
+                        'DEF:blah:bloo',
+                        'LINE:foo:bar']
+
+    SimpleRRD::Runner.should_receive(:run).with(*expected_command).and_return('ok')
+
+    @g.generate.should == 'ok'
   end
 end