Fix test failures on Linux CI for Maven Central publish

- Make 4 resolvePythonExecutable tests OS-aware (Windows/Unix layouts)
- Fix ensureMinPool() race: add instance before incrementing currentSize

Author: howtis

python-embed-runtime/src/main/java/io/github/howtis/pythonembed/PythonEmbedPool.java

@@ -1264,18 +1264,15 @@ public int healthCheck() {
     private void ensureMinPool() {
         if (closed) return;
 
-        int current;
-        while ((current = currentSize.get()) < minPool) {
-            if (currentSize.compareAndSet(current, current + 1)) {
-                try {
-                    PythonEmbed embed = createEmbed();
-                    instances.add(new PooledInstance(embed));
-                } catch (Exception e) {
-                    currentSize.decrementAndGet();
-                    logger.log(Level.WARNING,
-                            "Failed to create instance for minPool guarantee", e);
-                    break;
-                }
+        while (currentSize.get() < minPool) {
+            try {
+                PythonEmbed embed = createEmbed();
+                instances.add(new PooledInstance(embed));
+                currentSize.incrementAndGet();
+            } catch (Exception e) {
+                logger.log(Level.WARNING,
+                        "Failed to create instance for minPool guarantee", e);
+                break;
             }
         }
     }

python-embed-runtime/src/test/java/io/github/howtis/pythonembed/PythonProcessManagerTest.java

@@ -85,8 +85,15 @@ void cleanupTempDir() throws Exception {
     @Test
     void resolvePythonExecutable_venvLayout() throws Exception {
         tempDir = Files.createTempDirectory("test-venv-");
-        Path scriptsDir = Files.createDirectories(tempDir.resolve("Scripts"));
-        Path pythonExe = scriptsDir.resolve("python.exe");
+        boolean isWindows = System.getProperty("os.name", "").toLowerCase().contains("win");
+        Path pythonExe;
+        if (isWindows) {
+            Path scriptsDir = Files.createDirectories(tempDir.resolve("Scripts"));
+            pythonExe = scriptsDir.resolve("python.exe");
+        } else {
+            Path binDir = Files.createDirectories(tempDir.resolve("bin"));
+            pythonExe = binDir.resolve("python3");
+        }
         Files.createFile(pythonExe);
 
         String resolved = PythonProcessManager.resolvePythonExecutable(tempDir);
@@ -96,7 +103,14 @@ void resolvePythonExecutable_venvLayout() throws Exception {
     @Test
     void resolvePythonExecutable_standaloneLayout() throws Exception {
         tempDir = Files.createTempDirectory("test-standalone-");
-        Path pythonExe = tempDir.resolve("python.exe");
+        boolean isWindows = System.getProperty("os.name", "").toLowerCase().contains("win");
+        Path pythonExe;
+        if (isWindows) {
+            pythonExe = tempDir.resolve("python.exe");
+        } else {
+            Path binDir = Files.createDirectories(tempDir.resolve("bin"));
+            pythonExe = binDir.resolve("python3");
+        }
         Files.createFile(pythonExe);
 
         String resolved = PythonProcessManager.resolvePythonExecutable(tempDir);
@@ -106,24 +120,41 @@ void resolvePythonExecutable_standaloneLayout() throws Exception {
     @Test
     void resolvePythonExecutable_venvLayoutPreferredOverStandalone() throws Exception {
         tempDir = Files.createTempDirectory("test-both-");
-        Path scriptsDir = Files.createDirectories(tempDir.resolve("Scripts"));
-        Path venvPy = scriptsDir.resolve("python.exe");
-        Files.createFile(venvPy);
-        Path standalonePy = tempDir.resolve("python.exe");
-        Files.createFile(standalonePy);
+        boolean isWindows = System.getProperty("os.name", "").toLowerCase().contains("win");
+        Path preferredPy;
+        if (isWindows) {
+            Path scriptsDir = Files.createDirectories(tempDir.resolve("Scripts"));
+            preferredPy = scriptsDir.resolve("python.exe");
+            Files.createFile(preferredPy);
+            Path standalonePy = tempDir.resolve("python.exe");
+            Files.createFile(standalonePy);
+        } else {
+            Path binDir = Files.createDirectories(tempDir.resolve("bin"));
+            preferredPy = binDir.resolve("python3");
+            Files.createFile(preferredPy);
+            Path fallbackPy = binDir.resolve("python");
+            Files.createFile(fallbackPy);
+        }
 
         String resolved = PythonProcessManager.resolvePythonExecutable(tempDir);
-        assertEquals(venvPy.toAbsolutePath().toString(), resolved,
-                "venv layout (Scripts/python.exe) should be preferred over standalone (root python.exe)");
+        assertEquals(preferredPy.toAbsolutePath().toString(), resolved,
+                "venv layout should be preferred over standalone");
     }
 
     @Test
     void resolvePythonExecutable_fallbackWhenNeitherExists() {
         tempDir = Path.of("nonexistent-" + System.nanoTime());
         String resolved = PythonProcessManager.resolvePythonExecutable(tempDir);
-        assertTrue(resolved.endsWith("Scripts/py" + "thon.exe")
-                || resolved.endsWith("Scripts\\py" + "thon.exe"),
-                "should fall back to Scripts/python.exe path: " + resolved);
+        boolean isWindows = System.getProperty("os.name", "").toLowerCase().contains("win");
+        if (isWindows) {
+            assertTrue(resolved.endsWith("Scripts/py" + "thon.exe")
+                    || resolved.endsWith("Scripts\\py" + "thon.exe"),
+                    "should fall back to Scripts/python.exe path: " + resolved);
+        } else {
+            assertTrue(resolved.endsWith("bin/python3")
+                    || resolved.endsWith("bin\\python3"),
+                    "should fall back to bin/python3 path: " + resolved);
+        }
     }
 
     @Test