TST: Add better test errors and messages

Author: MechCoder

mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/IndexedRowMatrix.scala

@@ -103,7 +103,8 @@ class IndexedRowMatrix(
       computeU: Boolean = false,
       rCond: Double = 1e-9): SingularValueDecomposition[IndexedRowMatrix, Matrix] = {
 
-    require(k >= 1, "k should be at least one.")
+    val n = numCols().toInt
+    require(k > 0 && k <= n, s"Requested k singular values but got k=$k and numCols=$n.")
     val indices = rows.map(_.index)
     val svd = toRowMatrix().computeSVD(k, computeU, rCond)
     val U = if (computeU) {

mllib/src/main/scala/org/apache/spark/mllib/linalg/distributed/RowMatrix.scala

@@ -212,7 +212,7 @@ class RowMatrix(
       tol: Double,
       mode: String): SingularValueDecomposition[RowMatrix, Matrix] = {
     val n = numCols().toInt
-    require(k > 0 && k <= n, s"Request up to n singular values but got k=$k and n=$n.")
+    require(k > 0 && k <= n, s"Requested k singular values but got k=$k and numCols=$n.")
 
     object SVDMode extends Enumeration {
       val LocalARPACK, LocalLAPACK, DistARPACK = Value

mllib/src/test/scala/org/apache/spark/mllib/linalg/distributed/IndexedRowMatrixSuite.scala

@@ -115,14 +115,11 @@ class IndexedRowMatrixSuite extends FunSuite with MLlibTestSparkContext {
 
   test("validate k in svd") {
     val A = new IndexedRowMatrix(indexedRows)
-    try {
-        A.computeSVD(-1)
-      } catch {
-        case ie: IllegalArgumentException =>
-      }
+    intercept[IllegalArgumentException] {
+      A.computeSVD(-1)
+    }
   }
 
-
   def closeToZero(G: BDM[Double]): Boolean = {
     G.valuesIterator.map(math.abs).sum < 1e-6
   }

mllib/src/test/scala/org/apache/spark/mllib/linalg/distributed/RowMatrixSuite.scala

@@ -173,12 +173,8 @@ class RowMatrixSuite extends FunSuite with MLlibTestSparkContext {
 
   test("validate k in svd") {
     for (mat <- Seq(denseMat, sparseMat)) {
-      for (mode <- Seq("auto", "local-svd", "local-eigs", "dist-eigs")) {
-        try {
-          mat.computeSVD(-1, computeU = true, 1e-6, 300, 1e-10, mode)
-          } catch {
-            case ie: IllegalArgumentException =>
-          }
+      intercept[IllegalArgumentException] {
+        mat.computeSVD(-1)
       }
     }
   }