Add recompilation test to user_api_test.

PiperOrigin-RevId: 613192683
Change-Id: Ibb44e1c2d63ac0afb7b5f3a15dff26378deb6c82

test/fixture.cc

@@ -207,7 +207,7 @@ mjtNum CompareModel(const mjModel* m1, const mjModel* m2,
 
   // compare ints
   #define X(name) \
-    if (m1->name != m2->name) {maxdif = 1.0; field = #name;}
+    if (m1->name != m2->name) {maxdif = m1->name - m2->name; field = #name;}
     MJMODEL_INTS
   #undef X
   if (maxdif > 0) return maxdif;

test/user/CMakeLists.txt

@@ -18,7 +18,12 @@ target_link_libraries(user_model_test fixture gmock absl::str_format)
 mujoco_test(user_objects_test)
 target_link_libraries(user_objects_test fixture gmock)
 
-mujoco_test(user_api_test)
+mujoco_test(
+  user_api_test
+  PROPERTIES
+  ENVIRONMENT
+  "MUJOCO_PLUGIN_DIR=$<TARGET_FILE_DIR:elasticity>"
+)
 target_link_libraries(user_api_test fixture gmock)
 
 mujoco_test(user_flex_test)

test/user/user_api_test.cc

@@ -14,16 +14,25 @@
 
 // Tests for user/user_api.cc.
 
+#include <array>
+#include <filesystem>
+#include <string>
+#include <vector>
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
+#include <absl/strings/match.h>
+#include <mujoco/mujoco.h>
 #include "src/user/user_api.h"
+#include "src/xml/xml.h"
+#include "src/xml/xml_numeric_format.h"
 #include "test/fixture.h"
 
 namespace mujoco {
 namespace {
 
 using ::testing::HasSubstr;
+using ::testing::NotNull;
 
 
 // ----------------------------- test set/get  --------------------------------
@@ -53,5 +62,59 @@ TEST_F(MujocoTest, ReadWriteData) {
   mjm_deleteModel(model);
 }
 
+// ------------------- test recompilation multiple files ----------------------
+TEST_F(PluginTest, RecompileCompare) {
+  // full precision float printing
+  FullFloatPrecision increase_precision;
+
+  // loop over all xml files in data
+  std::vector<std::string> paths = {GetTestDataFilePath("."),
+                                    GetModelPath(".")};
+  std::string ext(".xml");
+  for (auto const& path : paths) {
+    for (auto &p : std::filesystem::recursive_directory_iterator(path)) {
+      if (p.path().extension() == ext) {
+        std::string xml = p.path().string();
+
+        // if file is meant to fail, skip it
+        if (absl::StrContains(p.path().string(), "malformed_") ||
+            absl::StrContains(p.path().string(), "touch_grid") ||
+            absl::StrContains(p.path().string(), "cow") ||
+            absl::StrContains(p.path().string(), "discardvisual")) {
+          continue;
+        }
+
+        // load model
+        std::array<char, 1000> error;
+        mjmModel* model =
+            mjParseXML(xml.c_str(), nullptr, error.data(), error.size());
+
+        // compile twice
+        mjModel* m_old = mjm_compileModel(model, nullptr);
+        mjModel* m_new = mjm_compileModel(model, nullptr);
+
+        ASSERT_THAT(m_old, NotNull())
+            << "Failed to compile " << xml << ": " << error.data();
+        ASSERT_THAT(m_new, NotNull())
+            << "Failed to recompile " << xml << ": " << error.data();
+
+        // compare and delete
+        std::string field = "";
+        mjtNum result = CompareModel(m_old, m_new, field);
+        mjtNum tol = 0;
+        EXPECT_LE(result, tol)
+            << "Loaded and saved models are different!\n"
+            << "Affected file " << p.path().string() << '\n'
+            << "Different field: " << field << '\n';
+
+        // delete models
+        mjm_deleteModel(model);
+        mj_deleteModel(m_old);
+        mj_deleteModel(m_new);
+      }
+    }
+  }
+}
+
 }  // namespace
 }  // namespace mujoco