This is a testharness.js-based test.
Found 90 tests; 73 PASS, 17 FAIL, 0 TIMEOUT, 0 NOTRUN.
PASS URLSearchParams constructed with: test
PASS request.formData() with input: test
PASS response.formData() with input: test
PASS URLSearchParams constructed with: ﻿test=﻿
FAIL request.formData() with input: ﻿test=﻿ assert_array_equals: property 0, expected "﻿test" but got "test"
FAIL response.formData() with input: ﻿test=﻿ assert_array_equals: property 0, expected "﻿test" but got "test"
PASS URLSearchParams constructed with: %EF%BB%BFtest=%EF%BB%BF
PASS request.formData() with input: %EF%BB%BFtest=%EF%BB%BF
PASS response.formData() with input: %EF%BB%BFtest=%EF%BB%BF
FAIL URLSearchParams constructed with: %FE%FF assert_array_equals: property 0, expected "\ufffd\ufffd" but got "þÿ"
FAIL request.formData() with input: %FE%FF assert_array_equals: property 0, expected "\ufffd\ufffd" but got "þÿ"
FAIL response.formData() with input: %FE%FF assert_array_equals: property 0, expected "\ufffd\ufffd" but got "þÿ"
FAIL URLSearchParams constructed with: %FF%FE assert_array_equals: property 0, expected "\ufffd\ufffd" but got "ÿþ"
FAIL request.formData() with input: %FF%FE assert_array_equals: property 0, expected "\ufffd\ufffd" but got "ÿþ"
FAIL response.formData() with input: %FF%FE assert_array_equals: property 0, expected "\ufffd\ufffd" but got "ÿþ"
PASS URLSearchParams constructed with: †&†=x
PASS request.formData() with input: †&†=x
PASS response.formData() with input: †&†=x
FAIL URLSearchParams constructed with: %C2 assert_array_equals: property 0, expected "\ufffd" but got "Â"
FAIL request.formData() with input: %C2 assert_array_equals: property 0, expected "\ufffd" but got "Â"
FAIL response.formData() with input: %C2 assert_array_equals: property 0, expected "\ufffd" but got "Â"
FAIL URLSearchParams constructed with: %C2x assert_array_equals: property 0, expected "\ufffdx" but got "Âx"
FAIL request.formData() with input: %C2x assert_array_equals: property 0, expected "\ufffdx" but got "Âx"
FAIL response.formData() with input: %C2x assert_array_equals: property 0, expected "\ufffdx" but got "Âx"
FAIL URLSearchParams constructed with: _charset_=windows-1252&test=%C2x assert_array_equals: property 1, expected "\ufffdx" but got "Âx"
FAIL request.formData() with input: _charset_=windows-1252&test=%C2x assert_array_equals: property 1, expected "\ufffdx" but got "Âx"
FAIL response.formData() with input: _charset_=windows-1252&test=%C2x assert_array_equals: property 1, expected "\ufffdx" but got "Âx"
PASS URLSearchParams constructed with: 
PASS request.formData() with input: 
PASS response.formData() with input: 
PASS URLSearchParams constructed with: a
PASS request.formData() with input: a
PASS response.formData() with input: a
PASS URLSearchParams constructed with: a=b
PASS request.formData() with input: a=b
PASS response.formData() with input: a=b
PASS URLSearchParams constructed with: a=
PASS request.formData() with input: a=
PASS response.formData() with input: a=
PASS URLSearchParams constructed with: =b
PASS request.formData() with input: =b
PASS response.formData() with input: =b
PASS URLSearchParams constructed with: &
PASS request.formData() with input: &
PASS response.formData() with input: &
PASS URLSearchParams constructed with: &a
PASS request.formData() with input: &a
PASS response.formData() with input: &a
PASS URLSearchParams constructed with: a&
PASS request.formData() with input: a&
PASS response.formData() with input: a&
PASS URLSearchParams constructed with: a&a
PASS request.formData() with input: a&a
PASS response.formData() with input: a&a
PASS URLSearchParams constructed with: a&b&c
PASS request.formData() with input: a&b&c
PASS response.formData() with input: a&b&c
PASS URLSearchParams constructed with: a=b&c=d
PASS request.formData() with input: a=b&c=d
PASS response.formData() with input: a=b&c=d
PASS URLSearchParams constructed with: a=b&c=d&
PASS request.formData() with input: a=b&c=d&
PASS response.formData() with input: a=b&c=d&
PASS URLSearchParams constructed with: &&&a=b&&&&c=d&
PASS request.formData() with input: &&&a=b&&&&c=d&
PASS response.formData() with input: &&&a=b&&&&c=d&
PASS URLSearchParams constructed with: a=a&a=b&a=c
PASS request.formData() with input: a=a&a=b&a=c
PASS response.formData() with input: a=a&a=b&a=c
PASS URLSearchParams constructed with: a==a
PASS request.formData() with input: a==a
PASS response.formData() with input: a==a
PASS URLSearchParams constructed with: a=a+b+c+d
PASS request.formData() with input: a=a+b+c+d
PASS response.formData() with input: a=a+b+c+d
PASS URLSearchParams constructed with: %=a
PASS request.formData() with input: %=a
PASS response.formData() with input: %=a
PASS URLSearchParams constructed with: %a=a
PASS request.formData() with input: %a=a
PASS response.formData() with input: %a=a
PASS URLSearchParams constructed with: %a_=a
PASS request.formData() with input: %a_=a
PASS response.formData() with input: %a_=a
PASS URLSearchParams constructed with: %61=a
PASS request.formData() with input: %61=a
PASS response.formData() with input: %61=a
PASS URLSearchParams constructed with: %61+%4d%4D=
PASS request.formData() with input: %61+%4d%4D=
PASS response.formData() with input: %61+%4d%4D=
Harness: the test ran to completion.