Add test USD files.

tests/usda/fail-case/customData-novalue-001.usda

@@ -0,0 +1,24 @@
+#usda 1.0
+(
+    customLayerData = {
+        bool zUp = 1
+        string bora = "my string"
+        dictionary Maya = {
+            bool generated
+        }
+    }
+
+)
+
+def Xform "teapot" (
+    kind = "component"
+)
+{
+    def Mesh "Teapot" (
+    )
+    {
+        color3f[] primvars:displayColor = [(1, 1, 1)] (
+        )
+
+    }
+}

tests/usda/stage-meta-001.usda

@@ -0,0 +1,7 @@
+#usda 1.0
+(
+  upAxis = "Y"
+  framesPerSecond = 10
+  statTimeCode = 3
+  endTimeCode = 21
+)

tests/usda/stage-meta-upAxis-001.usda

@@ -0,0 +1,4 @@
+#usda 1.0
+(
+  upAxis = "Y"
+)