Add tests for CDI mode resolution

Signed-off-by: Evan Lezar <elezar@nvidia.com>

pkg/nvcdi/lib.go

@@ -31,6 +31,8 @@ type nvcdilib struct {
 	deviceNamer   DeviceNamer
 	driverRoot    string
 	nvidiaCTKPath string
+
+	infolib info.Interface
 }
 
 // New creates a new nvcdi library
@@ -54,6 +56,9 @@ func New(opts ...Option) Interface {
 	if l.nvidiaCTKPath == "" {
 		l.nvidiaCTKPath = "/usr/bin/nvidia-ctk"
 	}
+	if l.infolib == nil {
+		l.infolib = info.New()
+	}
 
 	switch l.resolveMode() {
 	case "nvml":
@@ -82,9 +87,7 @@ func (l *nvcdilib) resolveMode() (rmode string) {
 		l.logger.Infof("Auto-detected mode as %q", rmode)
 	}()
 
-	nvinfo := info.New()
-
-	isWSL, reason := nvinfo.HasDXCore()
+	isWSL, reason := l.infolib.HasDXCore()
 	l.logger.Debugf("Is WSL-based system? %v: %v", isWSL, reason)
 
 	if isWSL {

pkg/nvcdi/lib_test.go

@@ -0,0 +1,88 @@
+/**
+# Copyright (c) NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package nvcdi
+
+import (
+	"fmt"
+	"testing"
+
+	testlog "github.com/sirupsen/logrus/hooks/test"
+	"github.com/stretchr/testify/require"
+)
+
+func TestResolveMode(t *testing.T) {
+	logger, _ := testlog.NewNullLogger()
+
+	testCases := []struct {
+		mode string
+		// TODO: This should be a proper mock
+		hasDXCore bool
+		expected  string
+	}{
+		{
+			mode:      "auto",
+			hasDXCore: true,
+			expected:  "wsl",
+		},
+		{
+			mode:      "auto",
+			hasDXCore: false,
+			expected:  "nvml",
+		},
+		{
+			mode:      "nvml",
+			hasDXCore: true,
+			expected:  "nvml",
+		},
+		{
+			mode:      "wsl",
+			hasDXCore: false,
+			expected:  "wsl",
+		},
+		{
+			mode:      "not-auto",
+			hasDXCore: true,
+			expected:  "not-auto",
+		},
+	}
+
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("test case %d", i), func(t *testing.T) {
+			l := nvcdilib{
+				logger:  logger,
+				mode:    tc.mode,
+				infolib: infoMock(tc.hasDXCore),
+			}
+
+			require.Equal(t, tc.expected, l.resolveMode())
+		})
+	}
+}
+
+type infoMock bool
+
+func (i infoMock) HasDXCore() (bool, string) {
+	return bool(i), ""
+}
+
+func (i infoMock) HasNvml() (bool, string) {
+	panic("should not be called")
+}
+
+func (i infoMock) IsTegraSystem() (bool, string) {
+	panic("should not be called")
+}