refactored, pre-buffer reuse

flash/src/test/java/dev/relism/routing/PathUtilsTest.java

@@ -0,0 +1,63 @@
+package dev.relism.routing;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class PathUtilsTest {
+
+    // --- sanitize ---
+
+    @Test
+    void sanitize_nullOrBlank_returnsRoot() {
+        assertEquals("/", PathUtils.sanitize(null));
+        assertEquals("/", PathUtils.sanitize(""));
+        assertEquals("/", PathUtils.sanitize("   "));
+        assertEquals("/", PathUtils.sanitize("/"));
+    }
+
+    @Test
+    void sanitize_trimsWhitespaceAndEnsuresLeadingSlash() {
+        assertEquals("/users", PathUtils.sanitize(" users "));
+        assertEquals("/api", PathUtils.sanitize("api"));
+    }
+
+    @Test
+    void sanitize_removesTrailingSlash() {
+        assertEquals("/users", PathUtils.sanitize("/users/"));
+        assertEquals("/api/v1", PathUtils.sanitize("/api/v1/"));
+    }
+
+    @Test
+    void sanitize_collapsesMultipleSlashes() {
+        assertEquals("/a/b/c", PathUtils.sanitize("//a///b//c/"));
+    }
+
+    // --- join ---
+
+    @Test
+    void join_withRootBase_returnsSanitizedPath() {
+        assertEquals("/users", PathUtils.join("/", "/users/"));
+        assertEquals("/users", PathUtils.join("/", "users"));
+    }
+
+    @Test
+    void join_withRootPath_returnsSanitizedBase() {
+        assertEquals("/api", PathUtils.join("/api/", "/"));
+        assertEquals("/api", PathUtils.join("api", ""));
+    }
+
+    @Test
+    void join_preventsDoubleNamespace() {
+        // Path already starts with base
+        assertEquals("/api/users", PathUtils.join("/api", "/api/users"));
+        assertEquals("/api/users", PathUtils.join("/api/", "/api/users/"));
+    }
+
+    @Test
+    void join_concatenatesProperly() {
+        assertEquals("/api/users", PathUtils.join("/api", "users"));
+        assertEquals("/api/users", PathUtils.join("/api", "/users"));
+        assertEquals("/api/users", PathUtils.join("api", "users"));
+    }
+}