Define include in the sandbox module, fix #31.

src/Literate.jl

@@ -511,6 +511,12 @@ end
 
 function execute_notebook(nb)
     m = Module(gensym())
+    # eval(expr) is available in the REPL (i.e. Main) so we emulate that for the sandbox
+    Core.eval(m, :(eval(x) = Core.eval($m, x)))
+    # modules created with Module() does not have include defined
+    # abspath is needed since this will call `include_relative`
+    Core.eval(m, :(include(x) = Base.include($m, abspath(x))))
+
     io = IOBuffer()
 
     execution_count = 0

test/runtests.jl

@@ -628,6 +628,13 @@ end
                 lastidx = nextind(notebook, last(idx))
             end
 
+            # issue #31
+            write(inputfile, "include(\"issue31.jl\")")
+            write(joinpath(outdir, "issue31.jl"), "10 + 21")
+            Literate.notebook(inputfile, outdir)
+            notebook = read(joinpath(outdir, "inputfile.ipynb"), String)
+            @test occursin("\"data\": {\n      \"text/plain\": \"31\"\n     }", notebook)
+
             # test error when executing notebook
             write(inputfile, "for i in 1:10\n    println(i)")
             r = try