myx 0.4.0

A lean, beautiful terminal Spotify player
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254

use crate::ui::*;
use crate::*;
use ratatui::Terminal;

// -------------------------------------------------------- scroll_offset

/// Walk the cursor from `from` to `to` one row at a time, as the arrow keys
/// do, threading the offset through — the sticky viewport only makes sense
/// as a sequence. Returns the offset the walk ends on.
fn walk(mut offset: usize, from: usize, to: usize, cap: usize, total: usize) -> usize {
    let step = if to >= from { 1isize } else { -1 };
    let mut sel = from as isize;
    while sel != to as isize {
        sel += step;
        offset = scroll_offset(offset, sel as usize, cap, total, 3);
    }
    offset
}

#[test]
fn short_lists_never_scroll() {
    assert_eq!(scroll_offset(0, 4, 10, 5, 3), 0);
    assert_eq!(scroll_offset(0, 9, 10, 10, 3), 0, "total == cap still fits");
}

#[test]
fn top_of_a_long_list_stays_put() {
    // Nothing to reveal above row 0, so no margin is owed there.
    for sel in 0..=4 {
        assert_eq!(scroll_offset(0, sel, 8, 50, 3), 0, "sel={sel}");
    }
}

#[test]
fn scrolling_down_keeps_the_margin_below_the_cursor() {
    // cap=8, margin=3: the cursor may reach row 4, then the list moves.
    let offset = walk(0, 0, 20, 8, 50);
    assert_eq!(20 - offset, 4, "3 rows stay visible below the cursor");
}

#[test]
fn scrolling_back_up_keeps_the_margin_above_the_cursor() {
    let offset = walk(0, 0, 30, 8, 50);
    let offset = walk(offset, 30, 10, 8, 50);
    assert_eq!(10 - offset, 3, "3 rows stay visible above the cursor");
}

#[test]
fn the_cursor_moves_inside_the_viewport_before_the_list_does() {
    // The whole point of the sticky offset: a short move well inside the
    // window must not scroll at all.
    let offset = walk(0, 0, 30, 20, 100);
    assert_eq!(scroll_offset(offset, 20, 20, 100, 3), offset);
}

#[test]
fn the_end_of_the_list_is_reachable() {
    // The last row must still be selectable — the bottom margin cannot push
    // the viewport past the end.
    assert_eq!(walk(0, 0, 49, 8, 50), 42, "clamped to total - cap");
}

#[test]
fn the_cursor_is_always_inside_the_viewport() {
    // The invariant the renderer depends on: `selected` must be one of the
    // rows actually drawn — whatever the previous offset was, and however
    // absurd the configured margin is.
    for margin in [0usize, 3, 99] {
        for total in [1usize, 5, 40] {
            for cap in 1..12usize {
                for prev in 0..total {
                    for sel in 0..total {
                        let off = scroll_offset(prev, sel, cap, total, margin);
                        let shown = cap.min(total);
                        assert!(off <= total.saturating_sub(cap), "{margin}/{total}/{cap}");
                        assert!(
                            sel >= off && sel < off + shown,
                            "{margin}/{total}/{cap}/{prev}/{sel}"
                        );
                    }
                }
            }
        }
    }
}

// --------------------------------------------------------- render_loading

/// The rendered rows, trailing blanks trimmed, paired with their y.
fn loading_rows(w: u16, h: u16) -> Vec<(u16, String)> {
    use ratatui::backend::TestBackend;
    let mut term = Terminal::new(TestBackend::new(w, h)).expect("test terminal");
    term.draw(|f| render_loading(f, "connecting to Spotify", 0))
        .expect("draw");
    let buf = term.backend().buffer().clone();
    (0..h)
        .map(|y| {
            let line: String = (0..w).map(|x| buf[(x, y)].symbol()).collect();
            (y, line)
        })
        .filter(|(_, line)| !line.trim().is_empty())
        .collect()
}

#[test]
fn the_loading_screen_names_what_it_is_waiting_on() {
    let text = loading_rows(40, 12)
        .into_iter()
        .map(|(_, l)| l)
        .collect::<String>();
    assert!(text.contains("connecting to Spotify"), "{text}");
    assert!(text.contains(SPINNER[0]), "spinner missing");
    assert!(text.contains('\u{FF2D}'), "wordmark missing");
}

#[test]
fn the_loading_screen_is_centred_on_both_axes() {
    let (w, h) = (41u16, 13u16);
    let rows = loading_rows(w, h);
    assert_eq!(rows.len(), 2, "expected a wordmark row and a spinner row");
    for (y, line) in &rows {
        // Measured from the content's midpoint, not its margins: the
        // fullwidth wordmark leaves a blank continuation cell per letter.
        let first = line.chars().take_while(|c| *c == ' ').count();
        let last = line.trim_end().chars().count();
        let centre = (first + last) / 2;
        assert!(
            centre.abs_diff(w as usize / 2) <= 1,
            "row {y} centres at {centre}, screen centre {} ({line:?})",
            w / 2
        );
    }
    // Two rows of content, so the block straddles the middle of the screen.
    let mid = (rows[0].0 + rows[1].0) / 2;
    assert!(
        mid.abs_diff(h / 2) <= 1,
        "block sits at {mid}, screen mid {}",
        h / 2
    );
}

// ------------------------------------------------------------ retry_delay

#[test]
fn short_backoffs_are_waited_out_long_ones_are_not() {
    assert!(retry_delay(Some(1)).is_some());
    assert!(retry_delay(Some(5)).is_some());
    assert!(
        retry_delay(None).is_some(),
        "no header means a token bounce"
    );
    // Spotify answers with hours once a development-mode quota is spent;
    // sleeping on that froze a drill-in for minutes and failed anyway.
    assert!(retry_delay(Some(60)).is_none());
    assert!(retry_delay(Some(76_854)).is_none());
}

// ---------------------------------------------------------- scrub_target

#[test]
fn a_scrub_step_moves_by_the_step_size() {
    assert_eq!(scrub_target(10_000, 200_000, 5_000), 15_000);
    assert_eq!(scrub_target(10_000, 200_000, -5_000), 5_000);
}

#[test]
fn a_scrub_cannot_leave_the_track() {
    // Held keys walk into both walls; neither may underflow or overshoot.
    assert_eq!(scrub_target(2_000, 200_000, -5_000), 0);
    assert_eq!(scrub_target(198_000, 200_000, 5_000), 200_000);
    assert_eq!(scrub_target(0, 0, -5_000), 0);
}

// -------------------------------------------------------- drives_library

#[test]
fn zen_ignores_the_keys_that_only_move_the_hidden_library() {
    for code in [
        KeyCode::Tab,
        KeyCode::BackTab,
        KeyCode::Up,
        KeyCode::Down,
        KeyCode::Enter,
        KeyCode::Char('j'),
        KeyCode::Char('/'),
        KeyCode::Char('o'),
    ] {
        assert!(drives_library(code), "{code:?} only drives the library");
    }
}

#[test]
fn zen_keeps_playback_and_the_right_hand_pane() {
    for code in [
        KeyCode::Char(' '),
        KeyCode::Char('n'),
        KeyCode::Char('b'),
        KeyCode::Char('s'),
        KeyCode::Char('z'),
        KeyCode::Char('q'),
        KeyCode::Left,
        KeyCode::Right,
        // Retargets onto the playing track rather than going quiet.
        KeyCode::Char('a'),
    ] {
        assert!(!drives_library(code), "{code:?} must still work in zen");
    }
}

// ---------------------------------------------------------- ArtRepaint

#[test]
fn a_forced_repaint_blanks_the_box_before_redrawing_it() {
    // The wipe is the whole mechanism: re-encoding is byte-identical for
    // sixel and iTerm2, so a blank frame is the only thing the diff will
    // emit — and it takes the overlay's leftovers with it.
    assert_eq!(ArtRepaint::Wipe.advance(), ArtRepaint::Draw);
    assert_eq!(ArtRepaint::Draw.advance(), ArtRepaint::Idle);
    assert_eq!(ArtRepaint::Idle.advance(), ArtRepaint::Idle);
}

// ----------------------------------------------------------- should_draw

#[test]
fn input_redraws_at_the_next_terminal_refresh() {
    // What made a held arrow key scroll in jerks: the cursor had moved but
    // the frame was held back until the idle tick came round.
    assert!(should_draw(true, false, MIN_FRAME));
    assert!(!should_draw(
        true,
        false,
        MIN_FRAME - Duration::from_millis(1)
    ));
}

#[test]
fn an_untouched_screen_redraws_rarely() {
    assert!(!should_draw(false, false, ANIM_FRAME));
    assert!(should_draw(false, false, IDLE_REDRAW));
}

#[test]
fn animation_redraws_between_the_two() {
    assert!(should_draw(false, true, ANIM_FRAME));
    assert!(!should_draw(false, true, MIN_FRAME));
}

#[test]
fn a_fade_is_long_enough_to_be_smooth_at_the_animation_rate() {
    // Smoothness has to come from duration, not frame rate: every present
    // recomposes the viewport and the inline cover shimmers at 60fps.
    let steps = FADE_MS / ANIM_FRAME.as_millis() as u64;
    assert!(steps >= 30, "only {steps} steps of recolour");
}