ferridriver-test 0.4.0

E2E test runner for ferridriver. Playwright-compatible API, parallel workers, auto-retrying expect, fixtures, snapshots.
Documentation 
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

//! Tests for visual screenshot diffing.
//!
//! These tests mutate process-global env vars (`UPDATE_SNAPSHOTS`, `SNAPSHOT_DIR`)
//! so they run serialized behind a mutex.
#![allow(unsafe_code)]

use ferridriver_test::ct::server::ComponentServer;
use ferridriver_test::expect::{LocatorSnapshotMatchers, expect};

static TEST_MUTEX: tokio::sync::Mutex<()> = tokio::sync::Mutex::const_new(());

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn screenshot_creates_baseline_then_matches() {
  let _guard = TEST_MUTEX.lock().await;
  let tmp = std::env::temp_dir().join(format!("ferri_ss_{}", std::process::id()));
  let _ = std::fs::remove_dir_all(&tmp);
  std::fs::create_dir_all(&tmp).unwrap();

  // Serve a simple page.
  std::fs::write(
    tmp.join("index.html"),
    r#"<!DOCTYPE html><html><body style="margin:0;padding:20px;background:white">
    <div id="box" style="width:100px;height:100px;background:red"></div>
    </body></html>"#,
  )
  .unwrap();

  let snap_dir = tmp.join("__snapshots__");
  let server = ComponentServer::start(&tmp).await.unwrap();
  let browser = ferridriver::chromium()
    .launch(ferridriver::options::LaunchOptions::default())
    .await
    .unwrap();
  let page = browser.new_page_with_url(&server.url()).await.unwrap();

  // Point snapshots at our temp dir (no cwd change needed).
  unsafe {
    std::env::set_var("UPDATE_SNAPSHOTS", "1");
    std::env::set_var("SNAPSHOT_DIR", snap_dir.as_os_str());
  }

  // First call: creates baseline.
  let result = expect(&page.locator("#box", None)).to_have_screenshot("red_box").await;
  assert!(result.is_ok(), "first screenshot should create baseline: {result:?}");

  // Verify baseline file exists.
  assert!(snap_dir.join("red_box.png").exists(), "baseline PNG should exist");
  let baseline_size = std::fs::metadata(snap_dir.join("red_box.png")).unwrap().len();
  assert!(
    baseline_size > 100,
    "baseline should be a real PNG, got {baseline_size}B"
  );

  // Second call with same content: should match.
  unsafe {
    std::env::remove_var("UPDATE_SNAPSHOTS");
  }
  let result = expect(&page.locator("#box", None)).to_have_screenshot("red_box").await;
  assert!(result.is_ok(), "identical screenshot should match: {result:?}");

  unsafe {
    std::env::remove_var("SNAPSHOT_DIR");
  }
  let _ = browser.close(None).await;
  server.stop().await;
  let _ = std::fs::remove_dir_all(&tmp);
}

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn screenshot_detects_visual_change() {
  let _guard = TEST_MUTEX.lock().await;
  let tmp = std::env::temp_dir().join(format!("ferri_ss_diff_{}", std::process::id()));
  let _ = std::fs::remove_dir_all(&tmp);
  std::fs::create_dir_all(&tmp).unwrap();

  let snap_dir = tmp.join("__snapshots__");

  std::fs::write(
    tmp.join("index.html"),
    r#"<!DOCTYPE html><html><body style="margin:0;padding:20px;background:white">
    <div id="box" style="width:100px;height:100px;background:red"></div>
    </body></html>"#,
  )
  .unwrap();

  let server = ComponentServer::start(&tmp).await.unwrap();
  let browser = ferridriver::chromium()
    .launch(ferridriver::options::LaunchOptions::default())
    .await
    .unwrap();
  let page = browser.new_page_with_url(&server.url()).await.unwrap();

  // Create baseline.
  unsafe {
    std::env::set_var("UPDATE_SNAPSHOTS", "1");
    std::env::set_var("SNAPSHOT_DIR", snap_dir.as_os_str());
  }
  expect(&page.locator("#box", None))
    .to_have_screenshot("color_box")
    .await
    .unwrap();
  unsafe {
    std::env::remove_var("UPDATE_SNAPSHOTS");
  }

  // Change the color.
  page
    .evaluate(
      "() => { document.getElementById('box').style.background = 'blue'; }",
      ferridriver::protocol::SerializedArgument::default(),
      None,
    )
    .await
    .unwrap();

  // Should fail with pixel diff.
  let result = expect(&page.locator("#box", None))
    .to_have_screenshot("color_box")
    .await;
  assert!(result.is_err(), "changed screenshot should fail");

  let err = result.unwrap_err();
  assert!(err.message.contains("mismatch"), "error should mention mismatch");
  assert!(err.message.contains("pixels differ"), "error should report pixel count");
  assert!(err.screenshot.is_some(), "error should attach actual screenshot");

  // Verify diff image was saved.
  assert!(
    snap_dir.join("color_box-diff.png").exists(),
    "diff image should be saved"
  );
  assert!(
    snap_dir.join("color_box-actual.png").exists(),
    "actual image should be saved"
  );

  // Verify diff image has content.
  let diff_size = std::fs::metadata(snap_dir.join("color_box-diff.png")).unwrap().len();
  assert!(diff_size > 100, "diff PNG should be real, got {diff_size}B");

  unsafe {
    std::env::remove_var("SNAPSHOT_DIR");
  }
  let _ = browser.close(None).await;
  server.stop().await;
  let _ = std::fs::remove_dir_all(&tmp);
}

#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
async fn screenshot_size_mismatch_detected() {
  let _guard = TEST_MUTEX.lock().await;
  let tmp = std::env::temp_dir().join(format!("ferri_ss_size_{}", std::process::id()));
  let _ = std::fs::remove_dir_all(&tmp);
  std::fs::create_dir_all(&tmp).unwrap();

  let snap_dir = tmp.join("__snapshots__");

  std::fs::write(
    tmp.join("index.html"),
    r#"<!DOCTYPE html><html><body style="margin:0;padding:20px;background:white">
    <div id="box" style="width:100px;height:100px;background:green"></div>
    </body></html>"#,
  )
  .unwrap();

  let server = ComponentServer::start(&tmp).await.unwrap();
  let browser = ferridriver::chromium()
    .launch(ferridriver::options::LaunchOptions::default())
    .await
    .unwrap();
  let page = browser.new_page_with_url(&server.url()).await.unwrap();

  // Create baseline.
  unsafe {
    std::env::set_var("UPDATE_SNAPSHOTS", "1");
    std::env::set_var("SNAPSHOT_DIR", snap_dir.as_os_str());
  }
  expect(&page.locator("#box", None))
    .to_have_screenshot("size_box")
    .await
    .unwrap();
  unsafe {
    std::env::remove_var("UPDATE_SNAPSHOTS");
  }

  // Resize the element.
  page
    .evaluate(
      "() => { const b = document.getElementById('box'); b.style.width = '200px'; b.style.height = '200px'; }",
      ferridriver::protocol::SerializedArgument::default(),
      None,
    )
    .await
    .unwrap();

  // Should fail with size mismatch.
  let result = expect(&page.locator("#box", None)).to_have_screenshot("size_box").await;
  assert!(result.is_err(), "resized screenshot should fail");
  let err = result.unwrap_err();
  assert!(
    err.message.contains("size mismatch"),
    "error should mention size: {}",
    err.message
  );

  unsafe {
    std::env::remove_var("SNAPSHOT_DIR");
  }
  let _ = browser.close(None).await;
  server.stop().await;
  let _ = std::fs::remove_dir_all(&tmp);
}