Add direct stream testing

Author: loganharbour

tests/utils/xdr_test.C

@@ -10,6 +10,7 @@
 
 // C++ includes
 #include <vector>
+#include <sstream>
 
 using namespace libMesh;
 
@@ -23,20 +24,9 @@ public:
   CPPUNIT_TEST_SUITE_END();
 
 private:
-
-public:
-  void setUp()
-  {}
-
-  void tearDown()
-  {}
-
-  void testDataVec ()
+  template <typename ReadLambda, typename WriteLambda>
+  void test_read_write(ReadLambda & act_read, WriteLambda & act_write)
   {
-    LOG_UNIT_TEST;
-
-    std::vector<Real> vec = {libMesh::pi, 2*libMesh::pi, 3*libMesh::pi};
-
     // There was once a weird bug mutating our TestCommWorld in
     // a previous unit test, which turned *this* test into a race
     // condition.  Let's make sure that never happens again.
@@ -49,23 +39,65 @@ public:
         // Write to file
         {
           Xdr xdr("output.dat", WRITE);
-          xdr.data(vec, "# This is a comment");
+          act_write(xdr);
         }
 
         // Read from file
         {
           Xdr xdr("output.dat", READ);
-          std::vector<Real> vec_in;
-          xdr.data(vec_in);
+          act_read(xdr);
+        }
+      }
 
-          // Check that correct number of values were read in
-          CPPUNIT_ASSERT_EQUAL(vec_in.size(), vec.size());
+    // Test reading/writing to a stream directly on all processors
+    {
+      std::stringstream stream;
 
-          // Check that values were written/read with sufficient accuracy
-          for (auto i : index_range(vec_in))
-            LIBMESH_ASSERT_FP_EQUAL(vec[i], vec_in[i], TOLERANCE);
-        }
+      // Write to stream
+      {
+        std::ostream ostream(stream.rdbuf());
+        Xdr xdr(ostream);
+        act_write(xdr);
       }
+
+      // Rewind stream
+      stream.seekp(0);
+
+      // Read from stream
+      {
+        std::istream istream(stream.rdbuf());
+        Xdr xdr(istream);
+        act_read(xdr);
+      }
+    }
+  }
+
+public:
+  void setUp()
+  {}
+
+  void tearDown()
+  {}
+
+  void testDataVec ()
+  {
+    LOG_UNIT_TEST;
+
+    std::vector<Real> vec = {libMesh::pi, 2*libMesh::pi, 3*libMesh::pi};
+
+    auto act_write = [&vec](Xdr & xdr) { xdr.data(vec, "# This is a comment"); };
+    auto act_read = [&vec](Xdr & xdr) {
+      std::vector<Real> vec_in;
+      xdr.data(vec_in);
+
+      // Check that correct number of values were read in
+      CPPUNIT_ASSERT_EQUAL(vec_in.size(), vec.size());
+
+      // Check that values were written/read with sufficient accuracy
+      for (auto i : index_range(vec_in))
+        LIBMESH_ASSERT_FP_EQUAL(vec[i], vec_in[i], TOLERANCE); };
+
+    test_read_write(act_read, act_write);
   }
 
   void testDataStream ()
@@ -76,29 +108,21 @@ public:
     for (auto i : index_range(vec))
       vec[i] = static_cast<Real>(i+1) / vec.size();
 
-    // Test reading/writing on 1 processor
-    if (TestCommWorld->rank() == 0)
-      {
-        // Write to file. If "line_break" does not exactly divide the
-        // vector size, there will be one line with fewer values than
-        // the others.
-        {
-          Xdr xdr("output.dat", WRITE);
-          xdr.data_stream(vec.data(), vec.size(), /*line_break=*/16);
-        }
-
-        // Read from file. To use data_stream(), the storage needs to
-        // be pre-sized and the line_break parameter is ignored.
-        {
-          Xdr xdr("output.dat", READ);
-          std::vector<Real> vec_in(100);
-          xdr.data_stream(vec_in.data(), vec_in.size());
-
-          // Check that values were written/read correctly
-          for (auto i : index_range(vec_in))
-            LIBMESH_ASSERT_FP_EQUAL(vec[i], vec_in[i], TOLERANCE);
-        }
-      }
+    // Write. If "line_break" does not exactly divide the vector size,
+    // there will be one line with fewer values than the others.
+    auto act_write = [&vec](Xdr & xdr) {
+      xdr.data_stream(vec.data(), vec.size(), /*line_break=*/16); };
+    // Read. To use data_stream(), the storage needs to be pre-sized
+    // and the line_break parameter is ignored.
+    auto act_read = [&vec](Xdr & xdr) {
+      std::vector<Real> vec_in(100);
+      xdr.data_stream(vec_in.data(), vec_in.size());
+
+      // Check that values were written/read correctly
+      for (auto i : index_range(vec_in))
+        LIBMESH_ASSERT_FP_EQUAL(vec[i], vec_in[i], TOLERANCE); };
+
+    test_read_write(act_read, act_write);
   }
 };