u01: Implement global node counting

The test is not very pretty, I may think of something nicer (once I
learn how to do it).

u01/node.cpp

@@ -1,7 +1,19 @@
 #include <iostream>
+#include <sstream>
 
 #include "node.h"
 
+unsigned int node::node_id = 0;
+
+node::node(const std::string &name) : name(name) {
+  node_id++;
+  if (name.empty()) {
+    std::stringstream node_sm;
+    node_sm << "node_" << node_id;
+    this->name = node_sm.str();
+  }
+}
+
 node::~node() {
   std::cout << "enter ~node() of \"" << get_name() << "\"" << std::endl;
   for (node *child : children) {

u01/node.h

@@ -4,7 +4,7 @@
 
 class node {
 public:
-  node(const std::string &name);
+  node(const std::string &name = "");
   virtual ~node();
   std::string get_name() const;
   void set_name(const std::string new_name);
@@ -15,4 +15,5 @@ public:
 private:
   std::string name;
   std::vector<node *> children;
+  static unsigned int node_id;
 };

u01/tests.cpp

@@ -33,3 +33,24 @@ TEST_CASE("Get children") {
   }
   delete n;
 }
+
+TEST_CASE("Global node counting") {
+  node *n = new node();
+
+  // TODO: ensure this test starts at node_id 0 (currently this is undefined
+  // based on order the tests are run) for the time being, this gets the offset
+  int node_id_start = std::stoi(n->get_name().substr(5));
+  // this tests if the node id was correctly extracted
+  REQUIRE(n->get_name() == "node_" + std::to_string(node_id_start));
+
+  for (std::size_t i = 0; i < 5; i++) {
+    n->add_child(new node());
+  }
+  n->add_child(new node("explicit name"));
+  for (std::size_t i = 0; i < 5; i++) {
+    REQUIRE(n->get_child(i)->get_name() ==
+            "node_" + std::to_string(node_id_start + 1 + i));
+  }
+  REQUIRE(n->get_child(5)->get_name() == "explicit name");
+  delete n;
+}