[UnitTest] Add test for literal string serialization

interfaces/cython/cantera/test/test_composite.py

@@ -542,12 +542,11 @@ class TestSolutionSerialization(utilities.CanteraTest):
             # Check that items are ordered as expected
             self.assertEqual(
                 list(data),
-                ['name', 'thermo', 'elements', 'species', 'state', 'custom-field']
+                ["name", "thermo", "elements", "species", "state",
-            )
+                 "custom-field", "literal-string"]
-            self.assertEqual(
-                list(data['custom-field']),
-                ['first', 'second', 'last']
             )
+            self.assertEqual(list(data["custom-field"]), ["first", "second", "last"])
+            self.assertEqual(data["literal-string"], "spam\nand\neggs\n")
 
     def test_input_data_debye_huckel(self):
         soln = ct.Solution('thermo-models.yaml', 'debye-huckel-B-dot-ak')

test/data/ideal-gas.yaml

@@ -8,6 +8,10 @@ phases:
     first: true
     second: [3.0, 5.0]
     last: [100, 200, 300]
+  literal-string: |
+    spam
+    and
+    eggs
   species: [O2, NO, N2]
   state: {T: 500.0, P: 10 atm, X: {O2: 0.21, N2: 0.79}}
 
@@ -94,6 +98,9 @@ species:
     - [3.282537840E+00, 1.483087540E-03, -7.579666690E-07, 2.094705550E-10,
        -2.167177940E-14, -1.088457720E+03, 5.453231290E+00]
     note: "TPIS89"
+  another-literal-string: |
+    foo
+    bar
 
 - name: NO
   composition: {N: 1, O: 1}

test/general/test_serialization.cpp

@@ -58,6 +58,26 @@ TEST(YamlWriter, userDefinedFields)
     EXPECT_FALSE(spec2->transport->input.hasKey("bogus-field"));
 }
 
+TEST(YamlWriter, literalStrings)
+{
+    auto original = newSolution("ideal-gas.yaml", "simple");
+    YamlWriter writer;
+    writer.addPhase(original);
+    writer.toYamlFile("generated-literal.yaml");
+    auto duplicate = newSolution("generated-literal.yaml");
+    auto thermo1 = original->thermo();
+    auto thermo2 = duplicate->thermo();
+
+    EXPECT_EQ(thermo1->input()["literal-string"].asString(),
+              thermo2->input()["literal-string"].asString());
+
+    auto spec1 = thermo1->species("O2");
+    auto spec2 = thermo2->species("O2");
+
+    EXPECT_EQ(spec1->input["another-literal-string"].asString(),
+              spec2->input["another-literal-string"].asString());
+}
+
 TEST(YamlWriter, sharedSpecies)
 {
     auto original1 = newSolution("ideal-gas.yaml", "simple");