test(linux): check the resolutions parsed from xrandr output

Move the parsing of resolutions() into resolutions_from_xrandr(), which takes the xrandr output, so the test asserts the returned list instead of the captured mode lines. resolutions() runs xrandr and calls it; the parsing is unchanged.

src/platform/linux.rs

@@ -1940,17 +1940,23 @@ fn get_xrandr_conn_pat(name: &str) -> String {
     )
 }
 
-// The mode lines below an output. A mode name can have a suffix after its size, like the "i" of
-// "1920x1080i", so a TV's interlaced mode does not end the list.
-const XRANDR_MODES_PAT: &str = r"(?P<resolutions>(\s*\d+x\d+\S*\s+\d+.*\n)+)";
-
 pub fn resolutions(name: &str) -> Vec<Resolution> {
-    let resolutions_pat = XRANDR_MODES_PAT;
+    match run_cmds("xrandr --query | tr -s ' '") {
+        Ok(xrandr_output) => resolutions_from_xrandr(name, &xrandr_output),
+        Err(e) => {
+            log::error!("Failed to run xrandr query, {}", e);
+            vec![]
+        }
+    }
+}
+
+fn resolutions_from_xrandr(name: &str, xrandr_output: &str) -> Vec<Resolution> {
+    // A mode name can have a suffix after its size, like the "i" of "1920x1080i", so a TV's
+    // interlaced mode does not end the list.
+    let resolutions_pat = r"(?P<resolutions>(\s*\d+x\d+\S*\s+\d+.*\n)+)";
     let connected_pat = get_xrandr_conn_pat(name);
     let mut v = vec![];
     if let Ok(re) = Regex::new(&format!("{}{}", connected_pat, resolutions_pat)) {
-        match run_cmds("xrandr --query | tr -s ' '") {
-            Ok(xrandr_output) => {
         // There'are different kinds of xrandr output.
         /*
         1.
@@ -1974,7 +1980,7 @@ pub fn resolutions(name: &str) -> Vec<Resolution> {
 
         rdp0 connected primary 1920x1080+0+0 0mm x 0mm
             */
-                if let Some(caps) = re.captures(&xrandr_output) {
+        if let Some(caps) = re.captures(xrandr_output) {
             if let Some(resolutions) = caps.name("resolutions") {
                 let resolution_pat =
                     r"\s*(?P<width>\d+)x(?P<height>\d+)\s+(?P<rates>(\d+\.\d+\D*)+)\s*\n";
@@ -1983,8 +1989,7 @@ pub fn resolutions(name: &str) -> Vec<Resolution> {
                     return vec![];
                 };
                 for resolution_caps in resolution_re.captures_iter(resolutions.as_str()) {
-                            if let Some((width, height)) =
-                                get_width_height_from_captures(&resolution_caps)
+                    if let Some((width, height)) = get_width_height_from_captures(&resolution_caps)
                     {
                         let resolution = Resolution {
                             width,
@@ -1999,9 +2004,6 @@ pub fn resolutions(name: &str) -> Vec<Resolution> {
             }
         }
     }
-            Err(e) => log::error!("Failed to run xrandr query, {}", e),
-        }
-    }
 
     v
 }
@@ -2051,15 +2053,11 @@ HDMI-0 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis
  640x480 75.00 59.94
 DP-0 disconnected (normal left inverted right x axis y axis)
 ";
-        let re = Regex::new(&format!(
-            "{}{}",
-            get_xrandr_conn_pat("HDMI-0"),
-            XRANDR_MODES_PAT
-        ))
-        .unwrap();
-        let caps = re.captures(xrandr_output).unwrap();
-        assert!(caps["resolutions"].contains(" 1280x720 "));
-        assert!(caps["resolutions"].contains(" 640x480 "));
+        let sizes: Vec<_> = resolutions_from_xrandr("HDMI-0", xrandr_output)
+            .iter()
+            .map(|r| (r.width, r.height))
+            .collect();
+        assert_eq!(sizes, vec![(1920, 1080), (1280, 720), (640, 480)]);
     }
 }