Fix binding generation special cases (#1902)

* Make binding.go easier to test

* Fix non-deterministic namespace order for bindings

* Add binding tests

* Fix nested import structs, non-string map keys, and escape invalid variable names

Co-authored-by: Lea Anthony <lea.anthony@gmail.com>

v2/internal/binding/binding_test/binding_test.go

@@ -0,0 +1,51 @@
+package binding_test
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/wailsapp/wails/v2/internal/binding"
+	"github.com/wailsapp/wails/v2/internal/logger"
+)
+
+type BindingTest struct {
+	name        string
+	structs     []interface{}
+	exemptions  []interface{}
+	want        string
+	shouldError bool
+}
+
+func TestBindings_GenerateModels(t *testing.T) {
+
+	tests := []BindingTest{
+		EscapedNameTest,
+		ImportedStructTest,
+		ImportedSliceTest,
+		ImportedMapTest,
+		NestedFieldTest,
+		NonStringMapKeyTest,
+		SingleFieldTest,
+	}
+
+	testLogger := &logger.Logger{}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			b := binding.NewBindings(testLogger, tt.structs, tt.exemptions, false)
+			for _, s := range tt.structs {
+				err := b.Add(s)
+				require.NoError(t, err)
+			}
+			got, err := b.GenerateModels()
+			if (err != nil) != tt.shouldError {
+				t.Errorf("GenerateModels() error = %v, shouldError %v", err, tt.shouldError)
+				return
+			}
+			if !reflect.DeepEqual(strings.Fields(string(got)), strings.Fields(tt.want)) {
+				t.Errorf("GenerateModels() got = %v, want %v", string(got), tt.want)
+			}
+		})
+	}
+}