Merge pull request #14242 from JuliaLang/betternoerror

Improve message for at-test_throw fails

Author: IainNZ

base/test.jl

@@ -57,7 +57,7 @@ function Base.show(io::IO, t::Pass)
 end
 
 """
-    Pass
+    Fail
 
 The test condition was false, i.e. the expression evaluated to false or
 the correct exception was not thrown.
@@ -71,10 +71,14 @@ end
 function Base.show(io::IO, t::Fail)
     print_with_color(:red, io, "Test Failed\n")
     print(io, "  Expression: ", t.orig_expr)
-    if t.test_type == :test_throws
-        # Either no exception, or wrong exception
+    if t.test_type == :test_throws_wrong
+        # An exception was thrown, but it was of the wrong type
         print(io, "\n    Expected: ", t.expr)
         print(io, "\n      Thrown: ", typeof(t.value))
+    elseif t.test_type == :test_throws_nothing
+        # An exception was expected, but no exception was thrown
+        print(io, "\n    Expected: ", t.expr)
+        print(io, "\n  No exception thrown")
     elseif !isa(t.expr, Expr)
         # Maybe just a constant, like false
         print(io, "\n   Evaluated: ", t.expr)
@@ -212,14 +216,14 @@ function do_test_throws(predicate, orig_expr, bt, extype)
     try
         predicate()
         # If we hit this line, no exception was thrown. We treat
-        # this as equivalent to the wrong exception being thrown.
-        Fail(:test_throws, orig_expr, extype, nothing)
+        # this a failure equivalent to the wrong exception being thrown.
+        Fail(:test_throws_nothing, orig_expr, extype, nothing)
     catch err
         # Check the right type of exception was thrown
         if isa(err, extype)
             Pass(:test_throws, orig_expr, extype, err)
         else
-            Fail(:test_throws, orig_expr, extype, err)
+            Fail(:test_throws_wrong, orig_expr, extype, err)
         end
     end)
 end

test/test.jl

@@ -18,7 +18,7 @@ a[1,1,1,1,1] = 10
 
 @test rand() != rand()
 
-# Test printing of result types
+# Test printing of Pass results
 # Pass - constant
 @test contains(sprint(show, @test true), "Expression: true")
 # Pass - expression
@@ -28,6 +28,31 @@ a[1,1,1,1,1] = 10
 @test contains(sprint(show, @test_throws ErrorException error()),
                 "Thrown: ErrorException")
 
+# Test printing of Fail results
+type NoThrowTestSet <: Base.Test.AbstractTestSet
+    results::Vector
+    NoThrowTestSet(desc) = new([])
+end
+Base.Test.record(ts::NoThrowTestSet, t::Base.Test.Result) = (push!(ts.results, t); t)
+Base.Test.finish(ts::NoThrowTestSet) = ts.results
+fails = @testset NoThrowTestSet begin
+    # Fail - wrong exception
+    @test_throws OverflowError error()
+    # Fail - no exception
+    @test_throws OverflowError 1 + 1
+    # Fail - const
+    @test false
+    # Fail - comparison
+    @test 1+1 == 2+2
+end
+for i in 1:4
+    @test isa(fails[i], Base.Test.Fail)
+end
+@test contains(sprint(show, fails[1]), "Thrown: ErrorException")
+@test contains(sprint(show, fails[2]), "No exception thrown")
+@test contains(sprint(show, fails[3]), "Evaluated: false")
+@test contains(sprint(show, fails[4]), "Evaluated: 2 == 4")
+
 # Test printing of a TestSetException
 tse_str = sprint(show, Test.TestSetException(1,2,3))
 @test contains(tse_str, "1 passed")