No case clause matching when property testing

Questions / Help
1 
property "when a & b are arbitrary json objects; patch(a, diff(a,b)) == b" do
    check all(
            map_a <- map_of(boolean(), boolean()),
            map_b <- nonempty(map_of(boolean(), boolean()))
          ) do




      assert d = JsonDiffEx.diff(map_a,map_b)
      assert map_b = JsonDiffEx.patch(map_a, d)

(ExUnitProperties.Error) failed with generated values (after 1 successful run):

     * Clause:    map_a <- map_of(boolean(), boolean())
       Generated: %{true: false}
     
     * Clause:    map_b <- nonempty(map_of(boolean(), boolean()))
       Generated: %{false: false}
 
 got exception:
 
     ** (CaseClauseError) no case clause matching: [false, 0, 0]

Not sure what the problem is, i’m trying to check "when a & b are arbitrary json objects; patch(a, diff(a,b)) == b. New to elixir and property testing so thank you for the patience and help. Need to write a property test to check that this library works and not sure how to do it.

2

What version of JsonDiffEx are you using? Using the latest version from Github, those operations appear to work:

iex(6)> JsonDiffEx.diff %{true => false}, %{false => true}
%{false: [true], true: [false, 0, 0]}

iex(7)> JsonDiffEx.patch %{true => false}, v(6)
%{false: true}

A side question: is a map with boolean keys even valid JSON?

3

I have the latest version installed. Where the problem I think is the stream data. I am writing a property test to show that the JsonDiffEx library works on two json’s and it does but I am not sure how to generate the data to run for the property tests ( I am an intern)

check all(
            map_a <- map_of(boolean(), boolean()),
            map_b <- nonempty(map_of(boolean(), boolean()))
          ) do
4

It would be helpful to see the rest of the error message after:

 got exception:
 
     ** (CaseClauseError) no case clause matching: [false, 0, 0]

to see where the crash is happening.

5

stacktrace:
(json_diff_ex 0.5.3) lib/json_diff_ex.ex:252: anonymous fn/3 in JsonDiffEx.do_patch/2
(elixir 1.13.2) lib/map.ex:617: Map.update/4
(stdlib 3.17) maps.erl:410: :maps.fold_1/3
(json_diff_ex 0.5.3) lib/json_diff_ex.ex:251: JsonDiffEx.do_patch/2
hidden1/hidden2/hidden3/difftesting_test.exs:17: anonymous fn/3 in DifftestingTest.“property when a & b are arbitrary json objects; patch(a, diff(a,b)) == b”/1
(stream_data 0.5.0) lib/stream_data.ex:2148: StreamData.shrink_failure/6
(stream_data 0.5.0) lib/stream_data.ex:2108: StreamData.check_all/7
test/hidden1/hidden/difftesting_test.exs:8: (test)

6

Wherever it says hidden, is just internal libraries i’m not allowed to show

7

But is this helpful?

8

This is not the latest version of json_diff_ex - 0.5.3 was released in September 2016!

In particular, the line in that version that’s crashing is this case:

which was changed to match on [_, 0, 0] in that last clause in this PR included in version 0.6.5

9

Thank you so much.