Non-English based system languages cause the failure of running the test driver

[yuhow]

My current system default language is traditional Chinese.
By running the unit test of devenv, I would have the following output messages:

---

*** test file: test_init_var.sh
test_devenvroot
test_devenvflavor
test_devenvflavorroot
test_devenvcurrentroot
test_devenvlibrary_path_backup
test_devenvpath_backup
test_devenvprefix
test_devenvdlroot

Ran 8 tests.

OK
*** test file: test_bash_utils.sh
test_display_type
ASSERT:expected:<denenv_display is a function> but was:<>
shunit2:ERROR test_display_type() returned non-zero return code.
test_display
test_display_e
devenv shunit2 unittest
test_get_cmd_list
test_get_build_list
test_get_application_list
test_get_flavor_list

Ran 7 tests.

FAILED (failures=2)
*** test file: test_devenv_impl.sh
test_namemunge
test_nameremove

Ran 2 tests.

OK

---

By further checking the error message, we could know the failure was from test function 'test_display_type()' in tests/test_bash_utils.sh

---

test_display_type() {
expected=display is a function"
actual=$(type display | grep "is a")
assertEquals "${expected}" "${actual}"
}

---

This function tried to check the output of the following command:
$ type display

The expected output message requested by the unit test should be 'display is a function'

Since my system default language was traditional Chinese, the output message would be 'display 是一個函數'

So the unit test would be failed due to non-English system language.