Replacing require.nil in api layer (#16906)

* Replacing require.nil in api layer

* Fixing some tests

* Fixing tests

* Addressing PR review comments

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

api4/export_test.go

@@ -23,7 +23,7 @@ func TestListExports(t *testing.T) {
 
 	t.Run("no permissions", func(t *testing.T) {
 		exports, resp := th.Client.ListExports()
-		require.Error(t, resp.Error)
+		require.NotNil(t, resp.Error)
 		require.Equal(t, "api.context.permissions.app_error", resp.Error.Id)
 		require.Nil(t, exports)
 	})
@@ -40,11 +40,11 @@ func TestListExports(t *testing.T) {
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
 		exportDir := filepath.Join(dataDir, *th.App.Config().ExportSettings.Directory)
 		err := os.Mkdir(exportDir, 0700)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		defer os.RemoveAll(exportDir)
 
 		f, err := os.Create(filepath.Join(exportDir, "export.zip"))
-		require.Nil(t, err)
+		require.NoError(t, err)
 		f.Close()
 
 		exports, resp := c.ListExports()
@@ -60,7 +60,7 @@ func TestListExports(t *testing.T) {
 
 		exportDir := filepath.Join(dataDir, value+"new")
 		err := os.Mkdir(exportDir, 0700)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		defer os.RemoveAll(exportDir)
 
 		exports, resp := c.ListExports()
@@ -68,7 +68,7 @@ func TestListExports(t *testing.T) {
 		require.Empty(t, exports)
 
 		f, err := os.Create(filepath.Join(exportDir, "export.zip"))
-		require.Nil(t, err)
+		require.NoError(t, err)
 		f.Close()
 
 		exports, resp = c.ListExports()
@@ -84,7 +84,7 @@ func TestDeleteExport(t *testing.T) {
 
 	t.Run("no permissions", func(t *testing.T) {
 		ok, resp := th.Client.DeleteExport("export.zip")
-		require.Error(t, resp.Error)
+		require.NotNil(t, resp.Error)
 		require.Equal(t, "api.context.permissions.app_error", resp.Error.Id)
 		require.False(t, ok)
 	})
@@ -95,11 +95,11 @@ func TestDeleteExport(t *testing.T) {
 
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
 		err := os.Mkdir(exportDir, 0700)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		defer os.RemoveAll(exportDir)
 		exportName := "export.zip"
 		f, err := os.Create(filepath.Join(exportDir, exportName))
-		require.Nil(t, err)
+		require.NoError(t, err)
 		f.Close()
 
 		exports, resp := c.ListExports()
@@ -129,7 +129,7 @@ func TestDownloadExport(t *testing.T) {
 	t.Run("no permissions", func(t *testing.T) {
 		var buf bytes.Buffer
 		n, resp := th.Client.DownloadExport("export.zip", &buf, 0)
-		require.Error(t, resp.Error)
+		require.NotNil(t, resp.Error)
 		require.Equal(t, "api.context.permissions.app_error", resp.Error.Id)
 		require.Zero(t, n)
 	})
@@ -141,21 +141,21 @@ func TestDownloadExport(t *testing.T) {
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
 		var buf bytes.Buffer
 		n, resp := c.DownloadExport("export.zip", &buf, 0)
-		require.Error(t, resp.Error)
+		require.NotNil(t, resp.Error)
 		require.Equal(t, "api.export.export_not_found.app_error", resp.Error.Id)
 		require.Zero(t, n)
 	}, "not found")
 
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
 		err := os.Mkdir(exportDir, 0700)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		defer os.RemoveAll(exportDir)
 
 		data := randomBytes(t, 1024*1024)
 		var buf bytes.Buffer
 		exportName := "export.zip"
 		err = ioutil.WriteFile(filepath.Join(exportDir, exportName), data, 0600)
-		require.Nil(t, err)
+		require.NoError(t, err)
 
 		n, resp := c.DownloadExport(exportName, &buf, 0)
 		require.Nil(t, resp.Error)
@@ -165,14 +165,14 @@ func TestDownloadExport(t *testing.T) {
 
 	th.TestForSystemAdminAndLocal(t, func(t *testing.T, c *model.Client4) {
 		err := os.Mkdir(exportDir, 0700)
-		require.Nil(t, err)
+		require.NoError(t, err)
 		defer os.RemoveAll(exportDir)
 
 		data := randomBytes(t, 1024*1024)
 		var buf bytes.Buffer
 		exportName := "export.zip"
 		err = ioutil.WriteFile(filepath.Join(exportDir, exportName), data, 0600)
-		require.Nil(t, err)
+		require.NoError(t, err)
 
 		offset := 1024 * 512
 		n, resp := c.DownloadExport(exportName, &buf, int64(offset))
@@ -191,16 +191,16 @@ func BenchmarkDownloadExport(b *testing.B) {
 	exportDir := filepath.Join(dataDir, *th.App.Config().ExportSettings.Directory)
 
 	err := os.Mkdir(exportDir, 0700)
-	require.Nil(b, err)
+	require.NoError(b, err)
 	defer os.RemoveAll(exportDir)
 
 	exportName := "export.zip"
 	f, err := os.Create(filepath.Join(exportDir, exportName))
-	require.Nil(b, err)
+	require.NoError(b, err)
 	f.Close()
 
 	err = os.Truncate(filepath.Join(exportDir, exportName), 1024*1024*1024)
-	require.Nil(b, err)
+	require.NoError(b, err)
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {