diff --git a/datasetUtils/getDatasetDetails_test.go b/datasetUtils/getDatasetDetails_test.go
index 9c57945..3a0b468 100644
--- a/datasetUtils/getDatasetDetails_test.go
+++ b/datasetUtils/getDatasetDetails_test.go
@@ -3,6 +3,7 @@ package datasetUtils
 import (
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 )
 
@@ -25,12 +26,18 @@ func TestGetDatasetDetails_EmptyList(t *testing.T) {
 	client := &http.Client{}
 
 	// Call the function to be tested
-	datasets, _, _ := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	datasets, notFoundIds, err := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	if err != nil {
+		t.Errorf("Unexpected error: %s", err.Error())
+	}
 
 	// Check the result
 	if len(datasets) != 0 {
 		t.Errorf("Expected 0 datasets, got %d", len(datasets))
 	}
+	if len(notFoundIds) != 0 {
+		t.Errorf("")
+	}
 }
 
 func TestGetDatasetDetails_Non200StatusCode(t *testing.T) {
@@ -52,12 +59,18 @@ func TestGetDatasetDetails_Non200StatusCode(t *testing.T) {
 	client := &http.Client{}
 
 	// Call the function to be tested
-	datasets, _, _ := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	datasets, notFoundIds, err := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	if err == nil {
+		t.Errorf("Expected an error to be returned, got nil")
+	}
 
 	// Check the result
 	if len(datasets) != 0 {
 		t.Errorf("Expected 0 datasets, got %d", len(datasets))
 	}
+	if len(notFoundIds) != 0 {
+		t.Errorf("Expected 0 not found IDs, got %d", len(notFoundIds))
+	}
 }
 
 func TestGetDatasetDetails_DatasetNotFound(t *testing.T) {
@@ -79,12 +92,18 @@ func TestGetDatasetDetails_DatasetNotFound(t *testing.T) {
 	client := &http.Client{}
 
 	// Call the function to be tested
-	datasets, _, _ := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	datasets, notFoundIds, err := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	if err != nil {
+		t.Errorf("Unexpected error: %s", err.Error())
+	}
 
 	// Check the result
 	if len(datasets) != 0 {
 		t.Errorf("Expected 0 datasets, got %d", len(datasets))
 	}
+	if len(notFoundIds) != 1 {
+		t.Errorf("Expected 1 ID that was not found, got %d", len(notFoundIds))
+	}
 }
 
 func TestGetDatasetDetails_DatasetFound(t *testing.T) {
@@ -106,7 +125,10 @@ func TestGetDatasetDetails_DatasetFound(t *testing.T) {
 	client := &http.Client{}
 
 	// Call the function to be tested
-	datasets, _, _ := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	datasets, notFoundIds, err := GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
+	if err != nil {
+		t.Errorf("Unexpected error: %s", err.Error())
+	}
 
 	// Check the result
 	if len(datasets) != 1 {
@@ -117,4 +139,33 @@ func TestGetDatasetDetails_DatasetFound(t *testing.T) {
 			t.Errorf("Dataset details do not match expected values")
 		}
 	}
+	if len(notFoundIds) != 0 {
+		t.Errorf("Expected no IDs that couldn't be found, got %d", len(notFoundIds))
+	}
+}
+
+func TestGetDatasetDetails_FilterString(t *testing.T) {
+	accessToken := "testToken"
+	datasetList := []string{"123"}
+	ownerGroup := "group1"
+	expectedFilter := `{"where":{"pid":{"inq":["` + strings.Join(datasetList, `","`) + `"]},"ownerGroup":"` + ownerGroup + `"},"fields":{"pid":true,"sourceFolder":true,"size":true,"ownerGroup":true}}`
+
+	// Create a mock server
+	server := httptest.NewServer(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		filter := req.URL.Query().Get("filter")
+		if filter != expectedFilter {
+			t.Errorf("Filter does not match expected value - got: \"%s\", expected: \"%s\"", filter, expectedFilter)
+		}
+		// Send some response
+		rw.Write([]byte(`[{"Pid":"123","SourceFolder":"/path/to/dataset","Size":1024,"OwnerGroup":"group1","NumberOfFiles":10}]`))
+	}))
+	// Close the server when test finishes
+	defer server.Close()
+	APIServer := server.URL
+
+	// Create a new HTTP client
+	client := &http.Client{}
+
+	// Call the function to be tested
+	GetDatasetDetails(client, APIServer, accessToken, datasetList, ownerGroup)
 }