fix: add test case for bfs_search_tree_from (fixes #99)

Rakefile

@@ -26,6 +26,13 @@ Rake::TestTask.new do |t|
   t.verbose = true
 end
 
+# Test bfs_search_tree_from in isolation, to ensure that adjacency is not loaded by other tests.
+Rake::TestTask.new do |t|
+  t.libs << 'test'
+  t.pattern = 'test/traversal_bfs_require.rb'
+  t.verbose = true
+end
+
 # Git tagging
 
 desc 'Commit all changes as a new version commit. Tag the commit with v<version> tag'

lib/rgl/traversal.rb

@@ -117,9 +117,9 @@ def bfs_iterator(v = self.detect { |x| true })
     #
     # @return [DirectedAdjacencyGraph] which represents a BFS search tree starting at _v_.
     def bfs_search_tree_from(v)
-     unless defined?(DirectedAdjacencyGraph)
-         require 'rgl/adjyceny'
-     end
+      unless defined?(DirectedAdjacencyGraph)
+        require 'rgl/adjacency'
+      end
       bfs  = bfs_iterator(v)
       tree = DirectedAdjacencyGraph.new
 

test/traversal_bfs_require.rb

@@ -0,0 +1,29 @@
+require 'test/unit'
+
+# Do not require rgl/adjacency !
+require 'rgl/traversal'
+require 'rgl/implicit'
+
+include RGL
+
+# Cyclic graph with _n_ vertices. Need a concrete graph, that is not an AdjacencyGraph
+def cycle(n)
+  RGL::ImplicitGraph.new { |g|
+    g.vertex_iterator { |b| 0.upto(n - 1, &b) }
+    g.adjacent_iterator { |x, b| b.call((x + 1) % n) }
+    g.directed = true
+  }
+end
+
+class TestAdjacencyNotRequired < Test::Unit::TestCase
+
+  def setup
+    @dg = cycle(4)
+  end
+
+  def test_bfs_search_tree
+    # bfs_search_tree_from requires rgl/adjacency if not yet loaded.
+    assert_equal("(1-2)(2-3)(3-0)", @dg.bfs_search_tree_from(1).edges.sort.join)
+  end
+
+end