[USDC reader] Creat Over prim in default when specifier field is not set.

Add a unit tester for io-util.cc

src/usdc-reader.cc

@@ -2800,9 +2800,8 @@ bool USDCReader::Impl::ReconstructPrimSpecNode(int parent, int current, int leve
           PUSH_ERROR_AND_RETURN_TAG(kTag, "Invalid Specifier.");
         }
       } else {
-        PUSH_ERROR_AND_RETURN_TAG(kTag,
-                                  "`specifier` field is missing for FieldSets "
-                                  "with SpecType::Prim.");
+        // Default = Over Prim.
+        specifier = Specifier::Over;
       }
 
       std::string pTyName;
@@ -2981,6 +2980,7 @@ bool USDCReader::Impl::ReconstructPrimSpecNode(int parent, int current, int leve
       } else {
         // Seems Variant is only composed of Properties.
         // Create pseudo `def` Prim
+        // FIXME: default is `Over`?
         specifier = Specifier::Def;
       }
 

tests/unit/CMakeLists.txt

@@ -12,6 +12,7 @@ set(TEST_SOURCES
 	unit-value-types.cc
 	unit-xform.cc
 	unit-math.cc
+	unit-ioutil.cc
    )
 
 if (TINYUSDZ_WITH_PXR_COMPAT_API)

tests/unit/unit-ioutil.cc

@@ -0,0 +1,17 @@
+#ifdef _MSC_VER
+#define NOMINMAX
+#endif
+
+#define TEST_NO_MAIN
+#include "acutest.h"
+
+#include "unit-ioutil.h"
+#include "io-util.hh"
+
+using namespace tinyusdz;
+
+void ioutil_test(void) {
+  {
+    TEST_CHECK(io::JoinPath("./", "./dora") == "./dora");
+  }
+}

tests/unit/unit-ioutil.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void ioutil_test(void);

tests/unit/unit-main.cc

@@ -12,6 +12,7 @@
 #include "unit-customdata.h"
 #include "unit-handle-allocator.h"
 #include "unit-math.h"
+#include "unit-ioutil.h"
 
 #if defined(TINYUSDZ_WITH_PXR_COMPAT_API)
 #include "unit-pxr-compat-api.h"
@@ -31,6 +32,7 @@ TEST_LIST = {
   { "math_sin_pi_test", math_sin_pi_test },
   { "math_sin_cos_pi_test", math_sin_cos_pi_test },
   { "pathutil_test", pathutil_test },
+  { "ioutil_test", ioutil_test },
 #if defined(TINYUSDZ_WITH_PXR_COMPAT_API)
   { "pxr_compat_api_test", pxr_compat_api_test },
 #endif