pids_limit: Add test.

Signed-off-by: Shishir Mahajan <smahajan@roblox.com>

drivers/docker/driver_linux_test.go

@@ -45,6 +45,27 @@ func TestDockerDriver_authFromHelper(t *testing.T) {
 	require.Equal(t, "registry.local:5000", string(content))
 }
 
+func TestDockerDriver_PluginConfig_PidsLimit(t *testing.T) {
+	t.Parallel()
+
+	dh := dockerDriverHarness(t, nil)
+	driver := dh.Impl().(*Driver)
+	driver.config.PidsLimit = 5
+
+	task, cfg, ports := dockerTask(t)
+	defer freeport.Return(ports)
+	require.NoError(t, task.EncodeConcreteDriverConfig(cfg))
+
+	c, err := driver.createContainerConfig(task, cfg, "org/repo:0.1")
+	require.NoError(t, err)
+	require.Equal(t, 5, c.HostConfig.PidsLimit)
+
+	cfg.PidsLimit = 7
+	_, err = driver.createContainerConfig(task, cfg, "org/repo:0.1")
+	require.Error(t, err)
+	require.Contains(t, err.Error(), `pids_limit cannot be greater than nomad plugin config pids_limit`)
+}
+
 func TestDockerDriver_PidsLimit(t *testing.T) {
 	if !tu.IsCI() {
 		t.Parallel()