Prevent breaks when parsing recordings with invalid times

It would break parsing a getRecordings if one of them had an empty
startTime or endTime.

Author: daronco

lib/bigbluebutton_formatter.rb

@@ -49,7 +49,9 @@ def to_datetime(key)
         if value.is_a?(Numeric)
           result = value == 0 ? nil : DateTime.parse(Time.at(value/1000.0).to_s)
         else
-          if value.downcase == "null"
+          if (value.is_a?(Hash) || value.is_a?(Array)) && value.empty?
+            result = nil
+          elsif value.is_a?(String) && (value.empty? || value.downcase == 'null')
             result = nil
           else
             # note: just in case the value comes as a string in the format: "Thu Sep 01 17:51:42 UTC 2011"

spec/bigbluebutton_formatter_spec.rb

@@ -100,14 +100,43 @@
     it { hash[:param7].should == nil }
     it { hash[:param8].should == nil }
 
-    context "returns nil if the param doesn't exists" do
-      subject { BigBlueButton::BigBlueButtonFormatter.new({ :param => 1}) }
-      it { subject.to_datetime(:inexistent).should == nil }
-    end
+    context "returns nil if" do
+      context "the param doesn't exists" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new({ :param => 1}) }
+        it { subject.to_datetime(:inexistent).should == nil }
+      end
 
-    context "returns nil if the hash is nil" do
-      subject { BigBlueButton::BigBlueButtonFormatter.new(nil) }
-      it { subject.to_datetime(:inexistent).should == nil }
+      context "the hash is nil" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new(nil) }
+        it { subject.to_datetime(:inexistent).should == nil }
+      end
+
+      context "the value is an empty string" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new({ param1: '' }) }
+        it { subject.to_datetime(:param1).should == nil }
+      end
+
+      context "the value is nil" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new({ param1: nil }) }
+        it { subject.to_datetime(:param1).should == nil }
+      end
+
+      context "the value is an empty hash" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new({ param1: {} }) }
+        it { subject.to_datetime(:param1).should == nil }
+      end
+
+      context "the value is an empty array" do
+        subject { BigBlueButton::BigBlueButtonFormatter.new({ param1: [] }) }
+        it { subject.to_datetime(:param1).should == nil }
+      end
+
+      ['null', 'NULL'].each do |v|
+        context "the value is '#{v}'" do
+          subject { BigBlueButton::BigBlueButtonFormatter.new({ param1: v }) }
+          it { subject.to_datetime(:param1).should == nil }
+        end
+      end
     end
   end