add ability to specify a default screnshot size for autogenerated scr…

…eenshots

biloba.go

@@ -159,14 +159,34 @@ func BilobaConfigDisableFailureScreenshots() func(*Biloba) {
 }
 
 /*
-Pass BilobaConfigWithChromeConnection to [ConnectToChrome] to disable screenshots when Progress Reports are emitted
+Pass BilobaConfigFailureScreenshotsSize to [ConnectToChrome] to set the size for the screenshots generated on failure
+*/
+func BilobaConfigFailureScreenshotsSize(width, height int) func(*Biloba) {
+	return func(b *Biloba) {
+		b.failureScreenshotWidth = width
+		b.failureScreenshotHeight = height
+	}
+}
+
+/*
+Pass BilobaConfigDisableProgressReportScreenshots to [ConnectToChrome] to disable screenshots when Progress Reports are emitted
 */
 func BilobaConfigDisableProgressReportScreenshots() func(*Biloba) {
 	return func(b *Biloba) {
 		b.disableProgressReportScreenshots = true
 	}
 }
 
+/*
+Pass BilobaConfigProgressReportScreenshotSize to [ConnectToChrome] to set the size for the screenshots generated when a progress report is requested
+*/
+func BilobaConfigProgressReportScreenshotSize(width, height int) func(*Biloba) {
+	return func(b *Biloba) {
+		b.progressReportScreenshotWidth = width
+		b.progressReportScreenshotHeight = height
+	}
+}
+
 /*
 Call ConnectToChrome(GinkgoT()) to connect to a Chrome browser
 
@@ -268,6 +288,10 @@ type Biloba struct {
 	enableDebugLogging               bool
 	disableFailureScreenshots        bool
 	disableProgressReportScreenshots bool
+	failureScreenshotWidth           int
+	failureScreenshotHeight          int
+	progressReportScreenshotWidth    int
+	progressReportScreenshotHeight   int
 }
 
 func (b *Biloba) GomegaString() string {
@@ -430,7 +454,7 @@ func (b *Biloba) Close() error {
 
 func (b *Biloba) attachScreenshotsIfFailed() {
 	if b.gt.Failed() {
-		for _, screenshot := range b.safeAllTabScreenshots() {
+		for _, screenshot := range b.safeAllTabScreenshots(b.failureScreenshotWidth, b.failureScreenshotHeight) {
 			if screenshot.failure != "" {
 				b.gt.AddReportEntryVisibilityFailureOrVerbose(screenshot.failure)
 			} else {
@@ -442,7 +466,7 @@ func (b *Biloba) attachScreenshotsIfFailed() {
 
 func (b *Biloba) progressReporter() string {
 	out := ""
-	for _, screenshot := range b.safeAllTabScreenshots() {
+	for _, screenshot := range b.safeAllTabScreenshots(b.progressReportScreenshotWidth, b.progressReportScreenshotHeight) {
 		if screenshot.failure != "" {
 			out += b.gt.F("{{red}}" + screenshot.failure + "{{/}}\n")
 		} else {

docs/index.md

@@ -1720,7 +1720,6 @@ var result map[string]int
 b.Run("({a:1, b:2})", &result)
 ```
 
-
 ## Window Size, Screenshots, and Configuration
 
 There are a few other odds and ends to cover, let's dive in
@@ -1747,6 +1746,8 @@ b.SetWindowSize(width, height)
 
 this also accepts any [`chromedp.EmulateViewportOption`](https://pkg.go.dev/github.com/chromedp/chromedp#EmulateViewportOption) after `height`.  `b.SetWindowSize` automatically sets up a Ginkgo `DeferCleanup` to reset the window size when the spec ends.  You can query the window size of a tab at any time using `b.WindowSize()`.
 
+One quick hack to speed up a test suite is to use the _smallest_ viable window size to run the tests.  You can then pass `BilobaConfigFailureScreenshotsSize(width, height)` to `ConnectToChrome(...)` to configure the size of Biloba's automatically generated screenshots.  Biloba will scale the window up on failure, take a screenshot, then scale it back down to proceed with other tests.  As an anecdotal data-point a 30% speed-up was observed for a Biloba test suite against a complex web-app running in parallel when the screen-size was minimized in this way.
+
 ### Capturing Screenshots
 
 As discussed above, Biloba automatically emits screenshots when a spec fails or a progress report is requested.
@@ -1792,7 +1793,11 @@ and sit back and watch those windows appear and disappear as you run your specs.
 - `BilobaConfigEnableDebugLogging()` will send all Chrome DevTools protocol traffic to the `GinkgoWriter`.  This can be useful when debugging specs and/or implementing your own more advanced `chromedp` behavior.  Fair warning, though: these logs are verbose!
 - `BilobaConfigWithChromeConnection(cc ChromeConnection)` allows you to specify your own Chrome connection settings (typically a `WebSocketURL`)
 - `BilobaConfigDisableFailureScreenshots()` disables Biloba's screenshots on failure
+- `BilobaConfigDisableFailureScreenshots()` disables Biloba's screenshots on failure
 - `BilobaConfigDisableProgressReportScreenshots()` disables Biloba's screenshots when progress reports are requested
+- `BilobaConfigFailureScreenshotsSize(width, height)` specifies the window size to use when generating a screenshot on failure
+- `BilobaConfigProgressReportScreenshotSize(width, height)` specifies the window size to use when generating a screenshot when progress reports are requested
+
 
 
 {% endraw  %}

screenshots.go

@@ -49,17 +49,34 @@ type tabScreenshot struct {
 	failure          string
 }
 
-func (b *Biloba) safeAllTabScreenshots() []tabScreenshot {
+func (b *Biloba) safeAllTabScreenshots(width int, height int) []tabScreenshot {
 	out := []tabScreenshot{}
 	for _, tab := range b.AllTabs() {
 		ctx, cancel := context.WithTimeout(tab.Context, time.Second)
 		defer cancel()
+
+		var originalWidth, originalHeight int
+		if width > 0 && height > 0 {
+			originalWidth, originalHeight = b.WindowSize()
+			err := chromedp.Run(ctx, chromedp.EmulateViewport(int64(width), int64(height)))
+			if err != nil {
+				out = append(out, tabScreenshot{failure: fmt.Sprintf("failed to set window size: %s", err.Error())})
+				continue
+			}
+		}
 		var img []byte
 		var title string
 		err := chromedp.Run(ctx,
 			chromedp.Title(&title),
 			chromedp.FullScreenshot(&img, 100),
 		)
+		if width > 0 && height > 0 {
+			err := chromedp.Run(ctx, chromedp.EmulateViewport(int64(originalWidth), int64(originalHeight), chromedp.EmulatePortrait))
+			if err != nil {
+				out = append(out, tabScreenshot{failure: fmt.Sprintf("failed to reset window size: %s", err.Error())})
+				continue
+			}
+		}
 		if ctx.Err() != nil {
 			out = append(out, tabScreenshot{failure: "Timed out attempting to fetch screenshot for tab"})
 			continue