add tests for property filters

jvm/src/test/scala/org/scalacheck/PropertyFilterSpecification.scala

@@ -0,0 +1,88 @@
+/*-------------------------------------------------------------------------*\
+**  ScalaCheck                                                             **
+**  Copyright (c) 2007-2016 Rickard Nilsson. All rights reserved.          **
+**  http://www.scalacheck.org                                              **
+**                                                                         **
+**  This software is released under the terms of the Revised BSD License.  **
+**  There is NO WARRANTY. See the file LICENSE for the full text.          **
+\*------------------------------------------------------------------------ */
+
+package org.scalacheck
+
+import Prop.BooleanOperators
+
+object PropertyFilterSampleSpecification extends Properties("PropertyFilterSample") {
+
+  property("positive numbers") = Prop.forAll(Gen.posNum[Int]) { n => n > 0 }
+
+  property("negative numbers") = Prop.forAll(Gen.negNum[Int]) { n => n < 0 }
+
+  property("lowercase alpha characters") = Prop.forAll(Gen.alphaLowerChar) { c =>
+    c.toInt >= 97 && c.toInt <= 122
+  }
+}
+
+object PropertyFilterSpecification extends Properties("PropertyFilter") {
+
+  val nl = System.lineSeparator
+
+  private def diff(filter: Option[String], actual: Seq[String],
+    expected: Seq[String]): String = {
+    s"filter: ${filter.getOrElse("not supplied")}" +
+    s"${nl}expected values:$nl" +
+    s"\t${expected.mkString(s"$nl\t")}" +
+    s"${nl}actual values:$nl" +
+    s"\t${actual.mkString(s"$nl\t")}"
+  }
+
+  private def prop(filter: Option[String], actualNames: Seq[String],
+    expectedNames: Seq[String]): Prop = {
+    def lengthProp = actualNames.length == expectedNames.length
+
+    def props = actualNames.forall(expectedNames.contains)
+
+    (lengthProp && props) :| diff(filter, actualNames, expectedNames)
+  }
+
+  property("filter properties by predicate") =
+    Prop.forAllNoShrink(
+      Gen.option(
+        Gen.oneOf(
+          "PropertyFilterSample.*numbers",
+          "PropertyFilterSample.*alpha"))) { pf =>
+
+            val testParams =
+              Test.Parameters.default.
+                withPropFilter(pf)
+
+            val props =
+              Test.checkProperties(
+                testParams,
+                PropertyFilterSampleSpecification
+              )
+
+            val propNames = props.map(_._1)
+
+            if (pf.exists(_.contains("*numbers"))) {
+              val expected =
+                Seq(
+                  "PropertyFilterSample.positive numbers",
+                  "PropertyFilterSample.negative numbers"
+                )
+
+                prop(pf, propNames, expected)
+            } else if (pf.exists(_.contains("*alpha"))) {
+              val expected = Seq("PropertyFilterSample.lowercase alpha characters")
+
+              prop(pf, propNames, expected)
+            } else { //no filter
+              val expected = Seq(
+                  "PropertyFilterSample.positive numbers",
+                  "PropertyFilterSample.negative numbers",
+                  "PropertyFilterSample.lowercase alpha characters"
+                )
+
+              prop(pf, propNames, expected)
+            }
+  }
+}