settings, line
<link rel="help" href="https://w3c.github.io/webvtt/#collect-webvtt-cue-timings-and-settings">

assert_equals(cues.length, 46);

// Test starts with simple valid values
var valid_values = [
    -1,
    0,
    0,
    1,
    100,
    101,
    65536,
    4294967296,
    18446744073709552000,
    10000000000000000000000000000000000,
    1.5,
    Number.MAX_VALUE,
    -1 * Number.MAX_VALUE,
    Number.MIN_VALUE,
    0, // Less than Number.MIN_VALUE
];
valid_values.forEach(function(valid, index) {
    assert_equals(cues[index].line, valid, 'Failed with cue ' + index);
    assert_true(cues[index].snapToLines, 'Failed with cue ' + index);
});

// Then a set of invalid ones
var invalid_length = 23;
for (var i = 0; i < invalid_length; i++) {
    var index = valid_values.length + i;

    assert_equals(cues[index].line, 'auto', 'Failed with cue ' + index);
    assert_true(cues[index].snapToLines, 'Failed with cue ' + index);
}

// Then more specific tests
var index = valid_values.length + invalid_length;

assert_equals(cues[index].line, 0);
assert_false(cues[index].snapToLines);

assert_equals(cues[index + 1].line, 0);
assert_false(cues[index + 1].snapToLines);

assert_equals(cues[index + 2].line, 100);
assert_false(cues[index + 2].snapToLines);
assert_equals(cues[index + 2].lineAlign, 'start');

assert_equals(cues[index + 3].line, 100);
assert_false(cues[index + 3].snapToLines);
assert_equals(cues[index + 3].lineAlign, 'start');

assert_equals(cues[index + 4].line, 100);
assert_false(cues[index + 4].snapToLines);
assert_equals(cues[index + 4].lineAlign, 'center');

assert_equals(cues[index + 5].line, 100);
assert_false(cues[index + 5].snapToLines);
assert_equals(cues[index + 5].lineAlign, 'end');

assert_equals(cues[index + 6].line, Number.MIN_VALUE);
assert_false(cues[index + 6].snapToLines);

assert_equals(cues[index + 7].line, 0);
assert_false(cues[index + 7].snapToLines);

===
WEBVTT

NOTE valid

00:00:00.000 --> 00:00:01.000 line:-1
valid0

00:00:00.000 --> 00:00:01.000 line:0
valid1

00:00:00.000 --> 00:00:01.000 line:-0
valid2

00:00:00.000 --> 00:00:01.000 line:1
valid3

00:00:00.000 --> 00:00:01.000 line:100
valid4

00:00:00.000 --> 00:00:01.000 line:101
valid5

00:00:00.000 --> 00:00:01.000 line:65536
valid6

00:00:00.000 --> 00:00:01.000 line:4294967296
valid7

00:00:00.000 --> 00:00:01.000 line:18446744073709552000
valid8

00:00:00.000 --> 00:00:01.000 line:10000000000000000000000000000000000
valid9

00:00:00.000 --> 00:00:01.000 line:1.5
valid10

Number.MAX_VALUE
00:00:00.000 --> 00:00:01.000 line:179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
valid11

-1 * Number.MAX_VALUE
00:00:00.000 --> 00:00:01.000 line:-179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
valid12

Number.MIN_VALUE
00:00:00.000 --> 00:00:01.000 line:0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005
valid13

Less than Number.MIN_VALUE
00:00:00.000 --> 00:00:01.000 line:0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002
valid14

NOTE invalid

00:00:00.000 --> 00:00:01.000 line:65536%
invalid15

00:00:00.000 --> 00:00:01.000 line:4294967296%
invalid16

00:00:00.000 --> 00:00:01.000 line:18446744073709552000%
invalid17

00:00:00.000 --> 00:00:01.000 line:10000000000000000000000000000000000%
invalid18

00:00:00.000 --> 00:00:01.000 line:-0%
invalid19

00:00:00.000 --> 00:00:01.000 line:101%
invalid20

00:00:00.000 --> 00:00:01.000 line:1%-
invalid21

00:00:00.000 --> 00:00:01.000 line:1-
invalid22

00:00:00.000 --> 00:00:01.000 line:%1
invalid23

00:00:00.000 --> 00:00:01.000 line:1%%
invalid24

00:00:00.000 --> 00:00:01.000 line:0%0
invalid25

00:00:00.000 --> 00:00:01.000 line: 0%
invalid26

00:00:00.000 --> 00:00:01.000 line:0%x
invalid27

00:00:00.000 --> 00:00:01.000 line:-
invalid28

00:00:00.000 --> 00:00:01.000 line:%
invalid29

00:00:00.000 --> 00:00:01.000 line:1..5
invalid30

00:00:00.000 --> 00:00:01.000 line:.5
invalid31

00:00:00.000 --> 00:00:01.000 line:5.
invalid32

Greater than Number.MAX_VALUE
00:00:00.000 --> 00:00:01.000 line:179769313486231590000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
invalid33

Less than -1 * Number.MAX_VALUE
00:00:00.000 --> 00:00:01.000 line:-179769313486231590000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
invalid34

exponential notation
00:00:00.000 --> 00:00:01.000 line:1e2
invalid35

00:00:00.000 --> 00:00:01.000 line:100%,middle
invalid36

00:00:00.000 --> 00:00:01.000 line:100%,
invalid37

NOTE extra

00:00:00.000 --> 00:00:01.000 line:0%
text38

00:00:00.000 --> 00:00:01.000 line:00%
text39

00:00:00.000 --> 00:00:01.000 line:100%
text40

00:00:00.000 --> 00:00:01.000 line:100%,start
text41

00:00:00.000 --> 00:00:01.000 line:100%,center
text42

00:00:00.000 --> 00:00:01.000 line:100%,end
text43

Number.MIN_VALUE %
00:00:00.000 --> 00:00:01.000 line:0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000005%
text44

Less than Number.MIN_VALUE %
00:00:00.000 --> 00:00:01.000 line:0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000002%
text45