fix coverage test on nightly

Depends on JuliaLang/julia#42810 to pass. I did also observe some other
test failures I couldn't really explain.

Author: simeonschaub

Project.toml

@@ -15,6 +15,7 @@ julia = "1"
 [extras]
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
 Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
+DiffUtils = "8294860b-85a6-42f8-8c35-d911f667b5f6"
 Distributed = "8ba89e20-285c-5b6f-9357-94700520ee1b"
 HTTP = "cd3eb016-35fb-5094-929b-558a96fad6f3"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
@@ -27,4 +28,4 @@ Tensors = "48a634ad-e948-5137-8d70-aa71f2a747f4"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test", "Dates", "Distributed", "HTTP", "LinearAlgebra", "Mmap", "PyCall", "SHA", "SparseArrays", "Tensors", "TableReader", "DataFrames"]
+test = ["Test", "Dates", "DiffUtils", "Distributed", "HTTP", "LinearAlgebra", "Mmap", "PyCall", "SHA", "SparseArrays", "Tensors", "TableReader", "DataFrames"]

test/code_coverage/code_coverage.jl

@@ -8,6 +8,8 @@ let
     end
 end
 
+using DiffUtils
+
 @testset "code coverage" begin
     out = read(`$(Base.julia_cmd()) --startup=no --project=$(dirname(dirname(@__DIR__))) --code-coverage=user
                 $(joinpath(@__DIR__(), "coverage_example.jl"))`, String)
@@ -23,5 +25,8 @@ end
         cov_data = replace(cov_data, "\r\n" => "\n")
         expected = replace(cov_data, "\r\n" => "\n")
     end
+    if cov_data != expected
+        DiffUtils.diff(cov_data, expected)
+    end
     @test cov_data == expected
 end

test/code_coverage/coverage_example.jl.cov

@@ -7,9 +7,9 @@
         1             i % 3 == 0 && fizz()
         1             i % 5 == 0 && buzz()
         -         else
-        4             print(i, " ")
+        3             print(i, " ")
         -         end
-        -     end
+        4     end
         1     return n
         - end
         -