also capture standard output before error

src/Literate.jl

@@ -942,8 +942,8 @@ function execute_block(sb::Module, block::String; inputfile::String, fake_source
             if err isa LoadError # include_string may wrap error in LoadError
                 err = err.error
             end
-            error_output = "ERROR: " * sprint(showerror, err)
+            all_output = c.output * "\n\nERROR: " * sprint(showerror, err)
-            return nothing, error_output, disp.data
+            return nothing, all_output, disp.data
         else
            error("""
                  $(sprint(showerror, c.value))

test/runtests.jl

@@ -1462,8 +1462,8 @@ end end
 @testset "continue_on_error=true" begin
     input_with_error =
         """
-        # The following will error
+        # The following will print something, then error
-
+        print("I always wanted to calculate")
         sqrt(-1.0)
         """
     mktempdir(@__DIR__) do sandbox
@@ -1471,6 +1471,7 @@ end end
         write(inputfile, input_with_error)
         Literate.markdown(inputfile, sandbox; continue_on_error = true, execute = true)
         output_md = read(joinpath(sandbox, "input.md"), String)
+        @test occursin("I always wanted to calculate", output_md)
         @test occursin("ERROR: DomainError with -1.0", output_md)
     end
 end