Corrected names in testSingle.c to reflect part struct change.

tests/testSPHStep.c

@@ -61,9 +61,9 @@ struct cell *make_cell(size_t N, float cellSize, int offset[3], int id_offset) {
             offset[2] * cellSize + z * cellSize / N + cellSize / (2 * N);
         part->h = h;
         part->id = x * N * N + y * N + z + id_offset;
-        ++part;
         part->ti_begin = 0;
         part->ti_end = 1;
+        ++part;
       }
     }
   }
@@ -193,7 +193,7 @@ int main() {
   runner_do_ghost(&r, ci);
 
   message("h=%f rho=%f N_ngb=%f", p->h, p->rho, p->density.wcount);
-  message("c=%f", p->force.c);
+  message("soundspeed=%f", p->force.soundspeed);
 
   runner_doself2_force(&r, ci);
   runner_do_kick(&r, ci, 1);