feat: add solver core skeleton

tests/unit/results_containers_test.cpp

@@ -0,0 +1,69 @@
+#include <fesa/results/results.hpp>
+
+#include <stdexcept>
+
+namespace {
+
+int fail()
+{
+    return 1;
+}
+
+} // namespace
+
+int main()
+{
+    fesa::results::ResultStep step{"static"};
+    auto& frame = step.add_frame(1, 0.0);
+    if (step.name() != "static" ||
+        step.frames().size() != 1 ||
+        frame.frame_id() != 1 ||
+        frame.time() != 0.0) {
+        return fail();
+    }
+
+    frame.add_field_output({
+        "U",
+        fesa::results::FieldLocation::nodal,
+        {"ux", "uy"},
+        {1, 2},
+        {0.0, 0.1, 1.0, 1.1}
+    });
+    if (frame.field_outputs().size() != 1 ||
+        frame.field_outputs()[0].entity_ids[1] != 2 ||
+        frame.field_outputs()[0].values[3] != 1.1) {
+        return fail();
+    }
+
+    frame.add_history_output({"load-factor", {0.0, 1.0}, {0.0, 10.0}});
+    if (frame.history_outputs().size() != 1 ||
+        frame.history_outputs()[0].values[1] != 10.0) {
+        return fail();
+    }
+
+    try {
+        frame.add_field_output({
+            "bad",
+            fesa::results::FieldLocation::nodal,
+            {},
+            {1},
+            {0.0}
+        });
+        return fail();
+    } catch (const std::invalid_argument&) {
+    }
+
+    try {
+        frame.add_field_output({
+            "bad-shape",
+            fesa::results::FieldLocation::nodal,
+            {"ux", "uy"},
+            {1},
+            {0.0}
+        });
+        return fail();
+    } catch (const std::invalid_argument&) {
+    }
+
+    return 0;
+}