for (final Artifact a : artifacts) {
                if (a.getName().equals(artifact.getName()) && !a.getVersion().equals(artifact.getVersion())) {
                    try {
                        pluginHelper.deleteInstalledArtifact(a);
                    } catch (final Exception e) {
                        logger.warn("Failed to delete {}", a.getFileName(), e);
                    }
                }
            }
        }).start();

    /**
     * Deletes an installed artifact.
     *
     * @param artifact the artifact to delete
     * @throws PluginException if the artifact does not exist or deletion fails
     */
    public void deleteInstalledArtifact(final Artifact artifact) {
        final String fileName = artifact.getFileName();
        final Path jarPath = Paths.get(ResourceUtil.getPluginPath().toString(), fileName);
        if (!Files.exists(jarPath)) {

        PluginHelper testHelper = new PluginHelper();
        Artifact artifact = new Artifact("non-existent", "1.0.0");

        try {
            testHelper.deleteInstalledArtifact(artifact);
            fail("Expected PluginException");
        } catch (PluginException e) {
            assertTrue(e.getMessage().contains("does not exist"));
        }
    }

    @Test