Test layer index can contain filenames with spaces

Add tests to ensure that the layer index can support filenames that
contain spaces.

Closes gh-20827

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/java/org/springframework/boot/jarmode/layertools/IndexedLayersTests.java

@@ -76,6 +76,12 @@ class IndexedLayersTests {
 		assertThat(layers.getLayer(mockEntry("META-INF/a/sub/folder/and/a/file"))).isEqualTo("application");
 	}
 
+	@Test
+	void getLayerWhenFileHasSpaceReturnsLayer() throws Exception {
+		IndexedLayers layers = new IndexedLayers(getIndex());
+		assertThat(layers.getLayer(mockEntry("a b/c d"))).isEqualTo("application");
+	}
+
 	private String getIndex() throws Exception {
 		ClassPathResource resource = new ClassPathResource("test-layers.idx", getClass());
 		InputStreamReader reader = new InputStreamReader(resource.getInputStream());

spring-boot-project/spring-boot-tools/spring-boot-jarmode-layertools/src/test/resources/org/springframework/boot/jarmode/layertools/test-layers.idx

@@ -4,3 +4,4 @@
 - "application":
   - "BOOT-INF/classes/Demo.class"
   - "META-INF/"
+  - "a b/c d"