DataFrameSuite allows you to check if two DataFrames are equal. You can assert the DataFrames equality using method assertDataFrameEquals. When DataFrames contains doubles or Spark Mllib Vector, you can assert that the DataFrames approximately equal using method assertDataFrameApproximateEquals

DataFrameSuite.scala

package test.com.idlike.junit.df

import breeze.numerics.abs
import org.apache.spark.rdd.RDD
import org.apache.spark.sql.functions.col
import org.apache.spark.sql.{Column, DataFrame, Row}

/**
  * Created by Umberto on 06/02/2017.
  */

object DataFrameSuite {

  /**
    * Compares if two [[DataFrame]]s are equal.
    * This approach correctly handles cases where the DataFrames may have duplicate rows, rows in different orders, and/or columns in different orders.
    * 1. Check two schemas are equal
    * 2. Check the number of rows are equal
    * 3. Check there is no unequal rows
    *
    * @param a         DataFrame
    * @param b         DataFrame
    * @param isRelaxed Boolean
    * @return
    */
  def assertDataFrameEquals(a: DataFrame, b: DataFrame, isRelaxed: Boolean): Boolean = {

    try {

      a.rdd.cache
      b.rdd.cache

      // 1. Check the equality of two schemas
      if (!a.schema.toString().equalsIgnoreCase(b.schema.toString)) {
        return false
      }

      // 2. Check the number of rows in two dfs
      if (a.count() != b.count()) {
        return false
      }

      // 3. Check there is no unequal rows
      val aColumns: Array[String] = a.columns
      val bColumns: Array[String] = b.columns

      // To correctly handles cases where the DataFrames may have columns in different orders
      scala.util.Sorting.quickSort(aColumns)
      scala.util.Sorting.quickSort(bColumns)
      val aSeq: Seq[Column] = aColumns.map(col(_))
      val bSeq: Seq[Column] = bColumns.map(col(_))

      var a_prime: DataFrame = null
      var b_prime: DataFrame = null

      if (isRelaxed) {
        a_prime = a
        //            a_prime.show()
        b_prime = b
        //            a_prime.show()
      }
      else {
        // To correctly handles cases where the DataFrames may have duplicate rows and/or rows in different orders
        a_prime = a.sort(aSeq: _*).groupBy(aSeq: _*).count()
        //    a_prime.show()
        b_prime = b.sort(aSeq: _*).groupBy(bSeq: _*).count()
        //    a_prime.show()
      }

      val c1: Long = a_prime.except(b_prime).count()
      val c2: Long = b_prime.except(a_prime).count()

      if (c1 != c2 || c1 != 0 || c2 != 0) {
        return false
      }
    } finally {
      a.rdd.unpersist()
      b.rdd.unpersist()
    }

    true
  }

  /**
    * Compares if two [[DataFrame]]s containing double are equal.
    * 1. Check two schemas are equal
    * 2. Check the number of rows are equal
    * 3. Check there is no unequal rows
    *
    * @param tol max acceptable tolerance, should be less than 1.
    */

  def assertDataFrameApproximateEquals(a: DataFrame, b: DataFrame, tol: Double): Boolean = {

    try {

      a.rdd.cache
      b.rdd.cache

      // 1. Check the equality of two schemas
      if (!a.schema.toString().equalsIgnoreCase(b.schema.toString)) {
        return false
      }

      // 2. Check the number of rows in two dfs
      if (a.count() != b.count()) {
        return false
      }

      // 3. Check there is no unequal rows
      val aIndexValue = zipWithIndex(a.rdd)
      val bIndexValue = zipWithIndex(b.rdd)

      val unequalRDD = aIndexValue.join(bIndexValue).filter { case (idx, (r1, r2)) =>
        !DataFrameSuite.approxEquals(r1, r2, tol)
      }
      if (unequalRDD.take(1).length != 0) {
        return false;
      }

    } finally {
      a.rdd.unpersist()
      b.rdd.unpersist()
    }

    true

  }

  def zipWithIndex[U](rdd: RDD[U]) = rdd.zipWithIndex().map { case (row, idx) => (idx, row) }

  /**
    * Approximate equality, based on equals from [[Row]]
    *
    * @param r1
    * @param r2
    * @param tol
    * @return
    */
  def approxEquals(r1: Row, r2: Row, tol: Double): Boolean = {
    if (r1.length != r2.length) {
      return false
    } else {
      var idx = 0
      val length = r1.length
      while (idx < length) {
        if (r1.isNullAt(idx) != r2.isNullAt(idx))
          return false

        if (!r1.isNullAt(idx)) {
          val o1 = r1.get(idx)
          val o2 = r2.get(idx)
          o1 match {
            case b1: Array[Byte] =>
              if (!java.util.Arrays.equals(b1, o2.asInstanceOf[Array[Byte]])) return false

            case f1: Float =>
              if (java.lang.Float.isNaN(f1) != java.lang.Float.isNaN(o2.asInstanceOf[Float])) return false
              if (abs(f1 - o2.asInstanceOf[Float]) > tol) return false

            case d1: Double =>
              if (java.lang.Double.isNaN(d1) != java.lang.Double.isNaN(o2.asInstanceOf[Double])) return false
              if (abs(d1 - o2.asInstanceOf[Double]) > tol) return false

            case d1: java.math.BigDecimal =>
              if (d1.compareTo(o2.asInstanceOf[java.math.BigDecimal]) != 0) return false

            case d1: org.apache.spark.ml.linalg.Vector =>
              val arr1: Array[Double] = d1.toArray
              val arr2: Array[Double] = o2.asInstanceOf[org.apache.spark.ml.linalg.Vector].toArray
              if (arr1.length != arr2.length) return false
              for (i <- 0 to (arr1.length - 1)) {
                if (abs(arr1(i) - arr2(i)) > tol) return false
              }

            case _ =>
              if (o1 != o2) return false
          }
        }
        idx += 1
      }
    }
    true
  }

}

what is "isRelaxed"?

Line 49: "scala.util.Sorting.quickSort(aColumns)" -> "scala.util.Sorting.quickSort(bColumns)"

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Line 49: "scala.util.Sorting.quickSort(aColumns)" -> "scala.util.Sorting.quickSort(bColumns)"

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