diff --git a/pyproject.toml b/pyproject.toml
index 1934212..c612708 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -83,6 +83,7 @@ dev = [
     "responses",
     "bump-my-version",
     "jsonschema",
+    "pystac[validation]"
 ]
 
 [tool.pytest.ini_options]
diff --git a/tests/schemas/datacube/v2.2.0.json b/tests/schemas/datacube/v2.2.0.json
deleted file mode 100644
index c1bdc89..0000000
--- a/tests/schemas/datacube/v2.2.0.json
+++ /dev/null
@@ -1,622 +0,0 @@
-{
-  "$schema": "http://json-schema.org/draft-07/schema#",
-  "$id": "https://stac-extensions.github.io/datacube/v2.2.0/schema.json",
-  "title": "Datacube Extension",
-  "description": "STAC Datacube Extension for STAC Items and STAC Collections.",
-  "oneOf": [
-    {
-      "$comment": "This is the schema for STAC Items.",
-      "allOf": [
-        {
-          "type": "object",
-          "required": [
-            "type"
-          ],
-          "properties": {
-            "type": {
-              "const": "Feature"
-            }
-          }
-        },
-        {
-          "$ref": "#/definitions/stac_extensions"
-        }
-      ],
-      "anyOf": [
-        {
-          "type": "object",
-          "required": [
-            "properties"
-          ],
-          "properties": {
-            "properties": {
-              "allOf": [
-                {
-                  "$ref": "#/definitions/require_field"
-                },
-                {
-                  "$ref": "#/definitions/fields"
-                }
-              ]
-            }
-          }
-        },
-        {
-          "$comment": "This validates the fields in Item Assets.",
-          "required": [
-            "assets"
-          ],
-          "properties": {
-            "assets": {
-              "type": "object",
-              "not": {
-                "additionalProperties": {
-                  "not": {
-                    "allOf": [
-                      {
-                        "$ref": "#/definitions/require_field"
-                      },
-                      {
-                        "$ref": "#/definitions/fields"
-                      }
-                    ]
-                  }
-                }
-              }
-            }
-          }
-        }
-      ]
-    },
-    {
-      "$comment": "This is the schema for STAC Collections.",
-      "type": "object",
-      "allOf": [
-        {
-          "required": [
-            "type"
-          ],
-          "properties": {
-            "type": {
-              "const": "Collection"
-            }
-          }
-        },
-        {
-          "$ref": "#/definitions/stac_extensions"
-        }
-      ],
-      "anyOf": [
-        {
-          "$comment": "This is the schema for the top-level fields in a Collection.",
-          "allOf": [
-            {
-              "$ref": "#/definitions/require_field"
-            },
-            {
-              "$ref": "#/definitions/fields"
-            }
-          ]
-        },
-        {
-          "$comment": "This validates the fields in Collection Assets.",
-          "required": [
-            "assets"
-          ],
-          "properties": {
-            "assets": {
-              "type": "object",
-              "not": {
-                "additionalProperties": {
-                  "not": {
-                    "allOf": [
-                      {
-                        "$ref": "#/definitions/require_field"
-                      },
-                      {
-                        "$ref": "#/definitions/fields"
-                      }
-                    ]
-                  }
-                }
-              }
-            }
-          }
-        },
-        {
-          "$comment": "This is the schema for the fields in Item Asset Definitions.",
-          "required": [
-            "item_assets"
-          ],
-          "properties": {
-            "item_assets": {
-              "type": "object",
-              "not": {
-                "additionalProperties": {
-                  "not": {
-                    "allOf": [
-                      {
-                        "$ref": "#/definitions/require_any_field"
-                      },
-                      {
-                        "$ref": "#/definitions/fields"
-                      }
-                    ]
-                  }
-                }
-              }
-            }
-          }
-        },
-        {
-          "$comment": "This is the schema for the fields in Summaries. By default, only checks the existance of the properties, but not the schema of the summaries.",
-          "required": [
-            "summaries"
-          ],
-          "properties": {
-            "summaries": {
-              "$ref": "#/definitions/require_any_field"
-            }
-          }
-        }
-      ]
-    }
-  ],
-  "definitions": {
-    "stac_extensions": {
-      "type": "object",
-      "required": [
-        "stac_extensions"
-      ],
-      "properties": {
-        "stac_extensions": {
-          "type": "array",
-          "contains": {
-            "const": "https://stac-extensions.github.io/datacube/v2.2.0/schema.json"
-          }
-        }
-      }
-    },
-    "require_any_field": {
-      "$comment": "Please list all fields here so that we can force the existance of one of them in other parts of the schemas.",
-      "anyOf": [
-        {"required": ["cube:dimensions"]},
-        {"required": ["cube:variables"]}
-      ]
-    },
-    "require_field": {
-      "required": [
-        "cube:dimensions"
-      ]
-    },
-    "fields": {
-      "$comment": "Add your new fields here. Don't require them here, do that above in the corresponding schema.",
-      "type": "object",
-      "properties": {
-        "cube:dimensions": {
-          "$ref": "#/definitions/cube:dimensions"
-        },
-        "cube:variables": {
-          "$ref": "#/definitions/cube:variables"
-        }
-      },
-      "patternProperties": {
-        "^(?!cube:)": {}
-      },
-      "additionalProperties": false
-    },
-    "cube:dimensions": {
-      "type": "object",
-      "additionalProperties": {
-        "anyOf": [
-          {
-            "$ref": "#/definitions/vector_dimension"
-          },
-          {
-            "$ref": "#/definitions/horizontal_spatial_dimension"
-          },
-          {
-            "$ref": "#/definitions/vertical_spatial_dimension"
-          },
-          {
-            "$ref": "#/definitions/temporal_dimension"
-          },
-          {
-            "$ref": "#/definitions/additional_dimension"
-          }
-        ]
-      }
-    },
-    "cube:variables": {
-      "type": "object",
-      "additionalProperties": {
-          "$ref": "#/definitions/variable"
-      }
-    },
-    "additional_dimension": {
-      "title": "Additional Dimension Object",
-      "type": "object",
-      "anyOf": [
-        {
-          "required": [
-            "type",
-            "extent"
-          ]
-        },
-        {
-          "required": [
-            "type",
-            "values"
-          ]
-        }
-      ],
-      "not": {
-        "required": [
-          "axis"
-        ]
-      },
-      "properties": {
-        "type": {
-          "type": "string",
-          "not": {
-            "enum": [
-              "spatial",
-              "geometry"
-            ]
-          }
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "extent": {
-          "$ref": "#/definitions/extent_open"
-        },
-        "values": {
-          "$ref": "#/definitions/values"
-        },
-        "step": {
-          "$ref": "#/definitions/step"
-        },
-        "unit": {
-          "$ref": "#/definitions/unit"
-        },
-        "reference_system": {
-          "type": "string"
-        },
-        "dimensions": {
-          "type": "array",
-          "items": {
-            "type": [
-              "string"
-            ]
-          }
-        }
-      }
-    },
-    "horizontal_spatial_dimension": {
-      "title": "Horizontal Spatial Raster Dimension Object",
-      "type": "object",
-      "required": [
-        "type",
-        "axis",
-        "extent"
-      ],
-      "properties": {
-        "type": {
-          "$ref": "#/definitions/type_spatial"
-        },
-        "axis": {
-          "$ref": "#/definitions/axis_xy"
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "extent": {
-          "$ref": "#/definitions/extent_closed"
-        },
-        "values": {
-          "$ref": "#/definitions/values_numeric"
-        },
-        "step": {
-          "$ref": "#/definitions/step"
-        },
-        "reference_system": {
-          "$ref": "#/definitions/reference_system_spatial"
-        }
-      }
-    },
-    "vertical_spatial_dimension": {
-      "title": "Vertical Spatial Dimension Object",
-      "type": "object",
-      "anyOf": [
-        {
-          "required": [
-            "type",
-            "axis",
-            "extent"
-          ]
-        },
-        {
-          "required": [
-            "type",
-            "axis",
-            "values"
-          ]
-        }
-      ],
-      "properties": {
-        "type": {
-          "$ref": "#/definitions/type_spatial"
-        },
-        "axis": {
-          "$ref": "#/definitions/axis_z"
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "extent": {
-          "$ref": "#/definitions/extent_open"
-        },
-        "values": {
-          "$ref": "#/definitions/values"
-        },
-        "step": {
-          "$ref": "#/definitions/step"
-        },
-        "unit": {
-          "$ref": "#/definitions/unit"
-        },
-        "reference_system": {
-          "$ref": "#/definitions/reference_system_spatial"
-        }
-      }
-    },
-    "vector_dimension": {
-      "title": "Spatial Vector Dimension Object",
-      "type": "object",
-      "required": [
-        "type",
-        "bbox"
-      ],
-      "properties": {
-        "type": {
-          "type": "string",
-          "const": "geometry"
-        },
-        "axes": {
-          "type": "array",
-          "uniqueItems": true,
-          "items": {
-            "type": "string",
-            "enum": [
-              "x",
-              "y",
-              "z"
-            ]
-          }
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "bbox": {
-          "title": "Spatial extent",
-          "type": "array",
-          "oneOf": [
-            {
-              "minItems":4,
-              "maxItems":4
-            },
-            {
-              "minItems":6,
-              "maxItems":6
-            }
-          ],
-          "items": {
-            "type": "number"
-          }
-        },
-        "values": {
-          "type": "array",
-          "minItems": 1,
-          "items": {
-            "description": "WKT or Identifier",
-            "type": "string"
-          }
-        },
-        "geometry_types":  {
-          "type": "array",
-          "uniqueItems": true,
-          "items": {
-            "type": "string",
-            "enum": [
-              "Point",
-              "MultiPoint",
-              "LineString",
-              "MultiLineString",
-              "Polygon",
-              "MultiPolygon",
-              "GeometryCollection"
-            ]
-          }
-        },
-        "reference_system": {
-          "$ref": "#/definitions/reference_system_spatial"
-        }
-      }
-    },
-    "temporal_dimension": {
-      "title": "Temporal Dimension Object",
-      "type": "object",
-      "required": [
-        "type",
-        "extent"
-      ],
-      "not": {
-        "required": [
-          "axis"
-        ]
-      },
-      "properties": {
-        "type": {
-          "type": "string",
-          "const": "temporal"
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "values": {
-          "type": "array",
-          "minItems": 1,
-          "items": {
-            "type": "string"
-          }
-        },
-        "extent": {
-          "type": "array",
-          "minItems": 2,
-          "maxItems": 2,
-          "items": {
-            "type": [
-              "string",
-              "null"
-            ]
-          }
-        },
-        "step": {
-          "type": [
-            "string",
-            "null"
-          ]
-        }
-      }
-    },
-    "variable": {
-      "title": "Variable Object",
-      "type": "object",
-      "required": [
-        "dimensions"
-      ],
-      "properties": {
-        "variable_type": {
-          "type": "string",
-          "enum": [
-            "data",
-            "auxiliary"
-          ]
-        },
-        "description": {
-          "$ref": "#/definitions/description"
-        },
-        "dimensions": {
-          "type": "array",
-          "items": {
-            "type": "string"
-          }
-        },
-        "values": {
-          "type": "array",
-          "minItems": 1
-        },
-        "extent": {
-          "type": "array",
-          "minItems": 2,
-          "maxItems": 2,
-          "items": {
-            "type": [
-              "string",
-              "number",
-              "null"
-            ]
-          }
-        },
-        "unit": {
-          "$ref": "#/definitions/unit"
-        }
-      }
-    },
-    "type_spatial": {
-      "type": "string",
-      "const": "spatial"
-    },
-    "axis_xy": {
-      "type": "string",
-      "enum": [
-        "x",
-        "y"
-      ]
-    },
-    "axis_z": {
-      "type": "string",
-      "const": "z"
-    },
-    "extent_closed": {
-      "type": "array",
-      "minItems": 2,
-      "maxItems": 2,
-      "items": {
-        "type": "number"
-      }
-    },
-    "extent_open": {
-      "type": "array",
-      "minItems": 2,
-      "maxItems": 2,
-      "items": {
-        "type": [
-          "number",
-          "null"
-        ]
-      }
-    },
-    "values_numeric": {
-      "type": "array",
-      "minItems": 1,
-      "items": {
-        "type": "number"
-      }
-    },
-    "values": {
-      "type": "array",
-      "minItems": 1,
-      "items": {
-        "oneOf": [
-          {
-            "type": "number"
-          },
-          {
-            "type": "string"
-          }
-        ]
-      }
-    },
-    "step": {
-      "type": [
-        "number",
-        "null"
-      ]
-    },
-    "unit": {
-      "type": "string"
-    },
-    "reference_system_spatial": {
-      "oneOf": [
-        {
-          "description": "WKT2",
-          "type": "string"
-        },
-        {
-          "description": "EPSG code",
-          "type": "integer",
-          "minimum": 0
-        },
-        {
-          "$ref": "https://proj.org/schemas/v0.4/projjson.schema.json"
-        }
-      ],
-      "default": 4326
-    },
-    "description": {
-      "type": "string"
-    }
-  }
-}
diff --git a/tests/test_directory_loader.py b/tests/test_directory_loader.py
index 361f123..88cf869 100644
--- a/tests/test_directory_loader.py
+++ b/tests/test_directory_loader.py
@@ -66,11 +66,18 @@ def test_directory_loader_populator_runner(prune_option: bool):
         assert request_mock.calls[1].request.path_url == "/stac/collections"
         assert request_mock.calls[1].request.body == file_contents["collection.json"]
 
-        assert request_mock.calls[2].request.path_url == f"/stac/collections/{base_col}/items"
-        assert request_mock.calls[2].request.body == file_contents["item-0.json"]
+        # NOTE:
+        #   Because directory crawler users 'os.walk', loading order is OS-dependant.
+        #   Since the order does not actually matter, consider item indices interchangeably.
+        req0_json = json.loads(request_mock.calls[2].request.body.decode())
+        req0_item = req0_json["id"]
+        item0_idx, item1_idx = (2, 3) if "sample-0" in req0_item else (3, 2)
 
-        assert request_mock.calls[3].request.path_url == f"/stac/collections/{base_col}/items"
-        assert request_mock.calls[3].request.body == file_contents["item-1.json"]
+        assert request_mock.calls[item0_idx].request.path_url == f"/stac/collections/{base_col}/items"
+        assert request_mock.calls[item0_idx].request.body == file_contents["item-0.json"]
+
+        assert request_mock.calls[item1_idx].request.path_url == f"/stac/collections/{base_col}/items"
+        assert request_mock.calls[item1_idx].request.body == file_contents["item-1.json"]
 
         if not prune_option:
             assert request_mock.calls[4].request.url == stac_host
@@ -79,8 +86,15 @@ def test_directory_loader_populator_runner(prune_option: bool):
             assert request_mock.calls[5].request.path_url == "/stac/collections"
             assert request_mock.calls[5].request.body == file_contents["nested/collection.json"]
 
-            assert request_mock.calls[6].request.path_url == f"/stac/collections/{nested_col}/items"
-            assert request_mock.calls[6].request.body == file_contents["nested/item-0.json"]
+            # NOTE:
+            #   Because directory crawler users 'os.walk', loading order is OS-dependant.
+            #   Since the order does not actually matter, consider item indices interchangeably.
+            req0_json = json.loads(request_mock.calls[6].request.body.decode())
+            req0_item = req0_json["id"]
+            item0_idx, item1_idx = (6, 7) if "sample-0" in req0_item else (7, 6)
+
+            assert request_mock.calls[item0_idx].request.path_url == f"/stac/collections/{nested_col}/items"
+            assert request_mock.calls[item0_idx].request.body == file_contents["nested/item-0.json"]
 
-            assert request_mock.calls[7].request.path_url == f"/stac/collections/{nested_col}/items"
-            assert request_mock.calls[7].request.body == file_contents["nested/item-1.json"]
+            assert request_mock.calls[item1_idx].request.path_url == f"/stac/collections/{nested_col}/items"
+            assert request_mock.calls[item1_idx].request.body == file_contents["nested/item-1.json"]