add a test acquisition that does not save images

src/main/java/org/micromanager/lightsheetmanager/api/AcquisitionManager.java

@@ -22,6 +22,16 @@ public interface AcquisitionManager {
      */
     Future<?> requestRun(boolean speedTest);
 
+    /**
+     * Request that a test acquisition is run.
+     *
+     * <p>A test acquisition runs a single time point and does not save anything to disk. The
+     * settings shown in the user interface are left unchanged.
+     *
+     * @return a future that completes when the acquisition finishes
+     */
+    Future<?> requestTestAcquisition();
+
     /**
      * Request the running acquisition to stop.
      */

src/main/java/org/micromanager/lightsheetmanager/gui/tabs/AcquisitionTab.java

@@ -184,7 +184,6 @@ private void createUserInterface() {
         swapTimingSettingsPanels(isUsingAdvancedTiming);
 
         btnRunOverviewAcq_.setEnabled(false); // TODO: re-enable when these features are put in
-        btnTestAcquisition_.setEnabled(false);
 
         // set ui sizes, should match the MigLayout constraints
         pnlChannelTable_.setAbsoluteSize(280, 400);
@@ -257,6 +256,7 @@ private void createEventHandlers() {
         btnOpenPlaylist_.setEnabled(false); // TODO: enable when playlist is implemented
 
         btnSpeedTest_.registerListener(() -> runAcquisition(true));
+        btnTestAcquisition_.registerListener(this::runTestAcquisition);
         btnRunOverviewAcq_.registerListener(() -> {
             // TODO: run the overview acq
         });
@@ -326,6 +326,7 @@ private void acqFinishedCallback() {
                 btnRunAcquisition_.setState(false);
                 btnPauseAcquisition_.setEnabled(false);
                 btnSpeedTest_.setEnabled(true);
+                btnTestAcquisition_.setEnabled(true);
             });
         } catch (InterruptedException e) {
             model_.studio().logs().logError("Acquisition was interrupted!");
@@ -337,7 +338,21 @@ private void acqFinishedCallback() {
     private void runAcquisition(boolean speedTest) {
         btnPauseAcquisition_.setEnabled(true);
         btnSpeedTest_.setEnabled(false);
-        Future<?> acqFinished = model_.acquisitions().requestRun(speedTest);
+        btnTestAcquisition_.setEnabled(false);
+        waitForAcquisition(model_.acquisitions().requestRun(speedTest));
+    }
+
+    private void runTestAcquisition() {
+        // this run is started from a button that is not the toggle, so select the toggle here
+        // or it reads "Start Acquisition" for as long as the test acquisition is running
+        btnRunAcquisition_.setState(true);
+        btnPauseAcquisition_.setEnabled(true);
+        btnSpeedTest_.setEnabled(false);
+        btnTestAcquisition_.setEnabled(false);
+        waitForAcquisition(model_.acquisitions().requestTestAcquisition());
+    }
+
+    private void waitForAcquisition(final Future<?> acqFinished) {
         // Launch new thread to update the button when the acquisition is complete
         new Thread(() -> {
             try {

src/main/java/org/micromanager/lightsheetmanager/model/UserSettings.java

@@ -134,17 +134,21 @@ public void loadFromJson(final String json, final boolean notify) {
      * Save user settings.
      */
     public void save() {
-        // make settings current before saving
-        model_.acquisitions().updateSettings();
-
         // settings key based on geometry type
         final GeometryType geometryType = model_.devices().adapter().geometry();
         final String key = SETTINGS_PREFIX + geometryType.toString().toUpperCase();
 
+        // Build from the builder, which holds what the user set in the user interface. The
+        // acquisition settings can carry run scoped overrides, for example a test acquisition
+        // turning saving off, and writing one of those to the profile would change the user's
+        // settings for every later session. Building here also means saving no longer rebuilds
+        // the settings a running acquisition is reading.
+        final ScapeAcquisitionSettings settings = model_.acquisitions().settingsBuilder().build();
+
         // save acquisition settings
-        settings_.putString(key, model_.acquisitions().settings().toJson());
+        settings_.putString(key, settings.toJson());
         model_.studio().logs().logDebugMessage("saved JSON to " + key + ": "
-                + model_.acquisitions().settings().toPrettyJson());
+                + settings.toPrettyJson());
 
         // save plugin settings
         settings_.putString(SETTINGS_PLUGIN, model_.pluginSettings().toJson());

src/main/java/org/micromanager/lightsheetmanager/model/acquisitions/AcquisitionEngine.java

@@ -52,6 +52,9 @@ public abstract class AcquisitionEngine implements AcquisitionManager, MMAcquist
     // cannot answer "is a run in flight?": the engines only assign it partway through run(), so it
     // stays null across all of setup() and the arming that follows.
     private volatile boolean acquisitionRequested_ = false;
+    // true while a test acquisition is in flight, read by updateSettings()
+    private volatile boolean testAcquisition_;
+
     // a stop asked for before the acquisition was started, acted on by the checks in requestRun()
     // and in each engine's run()
     private volatile boolean stopRequested_ = false;
@@ -282,7 +285,20 @@ public void updateSettings(final ScapeAcquisitionSettings acqSettings) {
      * Build the {@code DefaultAcquisitionSettingsSCAPE} with the builder and update settings.
      */
     public void updateSettings() {
-        acqSettings_ = asb_.build();
+        // Build fully before assigning: acqSettings_ is read from other threads, and a second
+        // assignment here would briefly publish the user's settings during a test acquisition.
+        ScapeAcquisitionSettings settings = asb_.build();
+        // Re-apply here and not at the call site: acqSettings_ is rebuilt from the builder at
+        // several points during a run, and the builder holds the user's settings, so an override
+        // applied once is discarded by the next rebuild.
+        if (testAcquisition_) {
+            settings = settings.copyBuilder()
+                    .saveImagesDuringAcquisition(false)
+                    .useTimePoints(false)
+                    .numTimePoints(1)
+                    .build();
+        }
+        acqSettings_ = settings;
     }
 
     public Future<?> requestRun() {
@@ -291,6 +307,15 @@ public Future<?> requestRun() {
 
     @Override
     public Future<?> requestRun(boolean speedTest) {
+        return requestRun(speedTest, false);
+    }
+
+    @Override
+    public Future<?> requestTestAcquisition() {
+        return requestRun(false, true);
+    }
+
+    private Future<?> requestRun(boolean speedTest, boolean testAcquisition) {
         // set here and not inside the task: a Stop clicked while the task is still queued, or
         // anywhere inside setup(), must find a run in flight
         acquisitionRequested_ = true;
@@ -308,6 +333,12 @@ public Future<?> requestRun(boolean speedTest) {
             long startNs = 0; // set alongside runId at START
 
             try {
+                // set inside the task and not at request time: the executor runs one task at a
+                // time, so this cannot reach a run that is already in flight, and the finally
+                // below only ever clears the request it belongs to. Set before updateSettings()
+                // so the first rebuild already carries the override.
+                testAcquisition_ = testAcquisition;
+
                 updateSettings(); // make sure settings are current
 
                 if (speedTest) {
@@ -363,6 +394,8 @@ public Future<?> requestRun(boolean speedTest) {
                     // cleared last of the run-state flags: while it is set, requestStop() treats
                     // a stop as something to act on rather than an error
                     acquisitionRequested_ = false;
+                    // cleared here so the next run rebuilds from the user's own settings
+                    testAcquisition_ = false;
                     // free the datastore so a large store isn't kept in memory (matches MM's
                     // AcqEngJAdapter.onAcquisitionEnded); also what the save guard checks to skip aborted/empty runs
                     datastore_ = null;