add tests for correct number of edges, fix a docstring

Author: Vincent Landau

src/rastergraphs.jl

@@ -327,7 +327,7 @@ here include `<`, `<=`, `==`, etc. The first argument to `condition` corresponds
 to the source vertex, and the second argument corresponds to the destination 
 vertex. So, if you only want to connect sources to destinations with a lower
 value in `raster` (e.g. in the case of developing a hydrologic flow 
-graph based on elevation), then you would use `<` for `condition`. Defaults to 
+graph based on elevation), then you would use `>` for `condition`. Defaults to 
 `is_data`, which results in neighbors being connected as long as they are not 
 NoData in `raster` (`raster.missingval`). Note that if using
 an inequality function (or any function where the result depends on argument 

test/weightedrasterdigraphs.jl

@@ -3,7 +3,7 @@ A_array = Array{Float64}(undef, (3, 4, 1))
 A_array[:,:,:] = [1, 3, 2, 0.5, 10, 8, 5, -9999, 3, 1, 2, 6]
 
 condition_array = Array{Float64}(undef, (3, 4, 1))
-condition_array[:,:,:] = [1, 0.5, 5, 2, 4, 8, 5, -9999, 2, 3, 6, 7]
+condition_array[:,:,:] = [1, 0.5, 5, 2, 4, 8, 5, -9999, 2, 3, 6, 6]
 
 x = X(1:4)
 y = Y(1:3)
@@ -34,6 +34,8 @@ rasgraph = weightedrastergraph(
 
 graph_edges = collect(edges(rasgraph))
 
+@test length(graph_edges) == 20 # Hard coded based on A_array and condition_array above...
+
 # Test that the edges are correct and have proper weights
 for i in 1:length(graph_edges)
     source_i = src(graph_edges[i])

test/weightedrastergraphs.jl

@@ -31,6 +31,8 @@ rasgraph = weightedrastergraph(weight_raster, connect_using_avg_weights = false)
 
 graph_edges = collect(edges(rasgraph))
 
+@test length(graph_edges) == 21 # hard coded based on A_array as defined above
+
 # Test that the edges are correct and have proper weights
 for i in 1:length(graph_edges)
     source_i = src(graph_edges[i])