Better testing framework, examples added as tests

idea/testData/psi/examples/UnionFind.jet

@@ -0,0 +1,33 @@
+class UnionFind {
+  private val data = IMutableList<Int>()
+
+  fun add() : Int {
+    val size = data.size
+    data.add(size)
+    size
+  }
+
+  private fun parent(x : Int) : Int {
+    val p = data[x];
+    if (p == x) {
+      return x;
+    }
+    val result = parent(p);
+    data[x] = result;
+  }
+
+  fun union(a : Int, b : Int) {
+    val pa = parent(a)
+    val pb = parent(b)
+    if (pa != pb) {
+      if (Random.nextInt().isOdd) {
+        data[pb] = pa
+      } else {
+        data[pa] = pb
+      }
+    }
+  }
+}
+
+val Int.isOdd : Boolean
+  get() = this % 2 != 0