Create internal errors package

internal/errors/errors_test.go

@@ -0,0 +1,147 @@
+// Copyright 2020 Kentaro Hibino. All rights reserved.
+// Use of this source code is governed by a MIT license
+// that can be found in the LICENSE file.
+
+package errors
+
+import "testing"
+
+func TestErrorString(t *testing.T) {
+	tests := []struct {
+		desc string
+		err  error
+		want string
+	}{
+		{
+			desc: "With Op, Code, and string",
+			err:  E(Op("rdb.DeleteTask"), NotFound, "cannot find task with id=123"),
+			want: "rdb.DeleteTask: NOT_FOUND: cannot find task with id=123",
+		},
+		{
+			desc: "With Op, Code and error",
+			err:  E(Op("rdb.DeleteTask"), NotFound, &TaskNotFoundError{Queue: "default", ID: "123"}),
+			want: `rdb.DeleteTask: NOT_FOUND: cannot find task with id=123 in queue "default"`,
+		},
+	}
+
+	for _, tc := range tests {
+		if got := tc.err.Error(); got != tc.want {
+			t.Errorf("%s: got=%q, want=%q", tc.desc, got, tc.want)
+		}
+	}
+}
+
+func TestErrorIs(t *testing.T) {
+	var ErrCustom = New("custom sentinel error")
+
+	tests := []struct {
+		desc   string
+		err    error
+		target error
+		want   bool
+	}{
+		{
+			desc:   "should unwrap one level",
+			err:    E(Op("rdb.DeleteTask"), ErrCustom),
+			target: ErrCustom,
+			want:   true,
+		},
+	}
+
+	for _, tc := range tests {
+		if got := Is(tc.err, tc.target); got != tc.want {
+			t.Errorf("%s: got=%t, want=%t", tc.desc, got, tc.want)
+		}
+	}
+}
+
+func TestErrorAs(t *testing.T) {
+	tests := []struct {
+		desc   string
+		err    error
+		target interface{}
+		want   bool
+	}{
+		{
+			desc:   "should unwrap one level",
+			err:    E(Op("rdb.DeleteTask"), NotFound, &QueueNotFoundError{Queue: "email"}),
+			target: &QueueNotFoundError{},
+			want:   true,
+		},
+	}
+
+	for _, tc := range tests {
+		if got := As(tc.err, &tc.target); got != tc.want {
+			t.Errorf("%s: got=%t, want=%t", tc.desc, got, tc.want)
+		}
+	}
+}
+
+func TestErrorPredicates(t *testing.T) {
+	tests := []struct {
+		desc string
+		fn   func(err error) bool
+		err  error
+		want bool
+	}{
+		{
+			desc: "IsTaskNotFound should detect presence of TaskNotFoundError in err's chain",
+			fn:   IsTaskNotFound,
+			err:  E(Op("rdb.ArchiveTask"), NotFound, &TaskNotFoundError{Queue: "default", ID: "9876"}),
+			want: true,
+		},
+		{
+			desc: "IsTaskNotFound should detect absence of TaskNotFoundError in err's chain",
+			fn:   IsTaskNotFound,
+			err:  E(Op("rdb.ArchiveTask"), NotFound, &QueueNotFoundError{Queue: "default"}),
+			want: false,
+		},
+		{
+			desc: "IsQueueNotFound should detect presence of QueueNotFoundError in err's chain",
+			fn:   IsQueueNotFound,
+			err:  E(Op("rdb.ArchiveTask"), NotFound, &QueueNotFoundError{Queue: "default"}),
+			want: true,
+		},
+	}
+
+	for _, tc := range tests {
+		if got := tc.fn(tc.err); got != tc.want {
+			t.Errorf("%s: got=%t, want=%t", tc.desc, got, tc.want)
+		}
+	}
+}
+
+func TestCanonicalCode(t *testing.T) {
+	tests := []struct {
+		desc string
+		err  error
+		want Code
+	}{
+		{
+			desc: "without nesting",
+			err:  E(Op("rdb.DeleteTask"), NotFound, &TaskNotFoundError{Queue: "default", ID: "123"}),
+			want: NotFound,
+		},
+		{
+			desc: "with nesting",
+			err:  E(FailedPrecondition, E(NotFound)),
+			want: FailedPrecondition,
+		},
+		{
+			desc: "returns Unspecified if err is not *Error",
+			err:  New("some other error"),
+			want: Unspecified,
+		},
+		{
+			desc: "returns Unspecified if err is nil",
+			err:  nil,
+			want: Unspecified,
+		},
+	}
+
+	for _, tc := range tests {
+		if got := CanonicalCode(tc.err); got != tc.want {
+			t.Errorf("%s: got=%s, want=%s", tc.desc, got, tc.want)
+		}
+	}
+}