Index: trunk/psLib/test/mathtypes/tap_psVectorSelect.c
===================================================================
--- trunk/psLib/test/mathtypes/tap_psVectorSelect.c	(revision 18332)
+++ trunk/psLib/test/mathtypes/tap_psVectorSelect.c	(revision 18333)
@@ -42,10 +42,44 @@
 }
 
+// Test that results of psVectorSelectInPlace match what you'd get from psVectorSort
+// 2 tests
+static void testSelectInPlace(int size,        // Size of vector
+                       int numNonzero   // Number of non-zero values
+                       )
+{
+    psMemId id = psMemGetId();
+
+    psVector *vector = psVectorAlloc(size, PS_TYPE_F32);
+    psVectorInit(vector, 0.0);
+    psRandom *rng = psRandomAlloc(PS_RANDOM_TAUS, 12345);
+    for (long i = 0; i < numNonzero; i++) {
+        long index = psRandomUniform(rng) * size;
+        vector->data.F32[index] = psRandomUniform(rng);
+    }
+    psFree(rng);
+
+    psVector *sorted = psVectorSort(NULL, vector); // Sorted vector
+    bool match = true;              // Everything matches
+    for (long i = 0; i < size && match; i++) {
+        psVectorSelectInPlace(vector, i);
+        if (vector->data.F32[i] != sorted->data.F32[i]) {
+            match = false;
+            diag("Rank %ld doesn't match: %f vs %f", i, vector->data.F32[i], sorted->data.F32[i]);
+        }
+    }
+    psFree(sorted);
+    psFree(vector);
+
+    ok(match, "All selections in-place match, size=%d, number non-zero=%d.", size, numNonzero);
+    ok(!psMemCheckLeaks(id, NULL, NULL, false), "no memory leaks");
+}
+
 
 int main(int argc, char *argv[])
 {
-    plan_tests(5 * 2);
+    plan_tests(6 * 2 + 6 * 2);
 
     testSelect(100, 0);
+    testSelect(100, 1);
     testSelect(100, 10);
     testSelect(100, 100);
@@ -53,4 +87,11 @@
     testSelect(137, 137);
 
+    testSelectInPlace(100, 0);
+    testSelectInPlace(100, 1);
+    testSelectInPlace(100, 10);
+    testSelectInPlace(100, 100);
+    testSelectInPlace(137, 13);
+    testSelectInPlace(137, 137);
+
     return PS_EXIT_SUCCESS;
 }