Fixes #220 : Add dataframe comparison without order

src/main/2.0/scala/com/holdenkarau/spark/testing/DataFrameSuiteBase.scala

@@ -170,6 +170,16 @@ trait DataFrameSuiteBaseLike extends SparkContextProvider
     }
   }
 
+  /**
+    * Compares if two [[DataFrame]]s are equal without caring about order of rows, by
+    * finding elements in one DataFrame that is not in the other. The resulting DataFrame
+    * should be empty inferring the two DataFrames have the same elements.
+    */
+  def assertDataFrameNoOrderEquals(expected: DataFrame, result: DataFrame) {
+    assertEmpty(expected.except(result).rdd.take(maxUnequalRowsToShow))
+    assertEmpty(result.except(expected).rdd.take(maxUnequalRowsToShow))
+  }
+
   /**
    * Zip RDD's with precise indexes. This is used so we can join two DataFrame's
    * Rows together regardless of if the source is different but still compare

src/test/1.3/scala/com/holdenkarau/spark/testing/SampleDataFrameTest.scala

@@ -37,6 +37,13 @@ class SampleDataFrameTest extends FunSuite with DataFrameSuiteBase {
     assertDataFrameEquals(input, input)
   }
 
+  test("dataframe should be equal with different order of rows") {
+    import sqlContext.implicits._
+    val input = sc.parallelize(inputList).toDF
+    val reverseInput = sc.parallelize(inputList.reverse).toDF
+    assertDataFrameNoOrderEquals(input, reverseInput)
+  }
+
   test("unequal dataframes should not be equal") {
     import sqlContext.implicits._
     val input = sc.parallelize(inputList).toDF
@@ -46,6 +53,18 @@ class SampleDataFrameTest extends FunSuite with DataFrameSuiteBase {
     }
   }
 
+  test("unequal dataframe with different order should not equal") {
+    import sqlContext.implicits._
+    val input = sc.parallelize(inputList).toDF
+    val input2 = sc.parallelize(List(inputList.head)).toDF
+    intercept[org.scalatest.exceptions.TestFailedException] {
+      assertDataFrameNoOrderEquals(input, input2)
+    }
+    intercept[org.scalatest.exceptions.TestFailedException] {
+      assertDataFrameNoOrderEquals(input2, input)
+    }
+  }
+
   test("dataframe approx expected") {
     import sqlContext.implicits._
     val input = sc.parallelize(inputList).toDF