diff --git a/src/intervals/arithmetic/trigonometric.jl b/src/intervals/arithmetic/trigonometric.jl
index 9350526dd..8a64da63b 100644
--- a/src/intervals/arithmetic/trigonometric.jl
+++ b/src/intervals/arithmetic/trigonometric.jl
@@ -565,9 +565,10 @@ function Base.atan(y::Interval, x::Interval)
     d = min(decoration(y), decoration(x), decoration(r))
     d = min(d,
             ifelse(in_interval(0, by),
-                ifelse(in_interval(0, bx), trv,
-                    ifelse(sup(bx) < 0, ifelse(inf(by) < 0, def, dac), d)),
-            d))
+                   ifelse(in_interval(0, bx),
+                          trv,
+                          ifelse(sup(bx) < 0, ifelse(inf(by) < 0, def, d), d)),
+                   d))
     t = isguaranteed(y) & isguaranteed(x)
     return _unsafe_interval(r, d, t)
 end
diff --git a/test/ITF1788_tests/libieeep1788_elem.jl b/test/ITF1788_tests/libieeep1788_elem.jl
index b214fbf9b..a98c27fbe 100644
--- a/test/ITF1788_tests/libieeep1788_elem.jl
+++ b/test/ITF1788_tests/libieeep1788_elem.jl
@@ -7144,7 +7144,8 @@ end
 
     @test atan(interval(bareinterval(-0.0, 1.0), com), interval(bareinterval(-0.0, -0.0), def)) === interval(bareinterval(0x1.921FB54442D18P+0, 0x1.921FB54442D19P+0), trv)
 
-    @test atan(interval(bareinterval(-0.0, 1.0), com), interval(bareinterval(-2.0, -0.1), com)) === interval(bareinterval(0x1.ABA397C7259DDP+0, 0x1.921FB54442D19P+1), dac)
+    @warn "The original test `atan2 [-0.0, 1.0]_com [-2.0, -0.1]_com = [0X1.ABA397C7259DDP+0, 0X1.921FB54442D19P+1]_dac` is wrong and has been modified. The result should have the decoration `com`"
+    @test atan(interval(bareinterval(-0.0, 1.0), com), interval(bareinterval(-2.0, -0.1), com)) === interval(bareinterval(0x1.ABA397C7259DDP+0, 0x1.921FB54442D19P+1), com)
 
     @test atan(interval(bareinterval(-0.0, 1.0), def), interval(bareinterval(-2.0, 0.0), com)) === interval(bareinterval(0x1.921FB54442D18P+0, 0x1.921FB54442D19P+1), trv)
 
diff --git a/test/generate_ITF1788.jl b/test/generate_ITF1788.jl
index 992021d76..0dca9e659 100644
--- a/test/generate_ITF1788.jl
+++ b/test/generate_ITF1788.jl
@@ -158,10 +158,18 @@ function parse_command(line)
     rhs = parse_rhs(rhs)
 
     expr = build_expression(lhs, rhs)
+    command = "@test $expr"
 
-    # one known broken test, unrelated to interval airthmetic
-    command = occursin("dot_nearest {0x10000000000001p0, 0x1p104} {0x0fffffffffffffp0, -1.0} = -1.0", line) ?
-        "@test_broken $expr" : "@test $expr"
+    if occursin("dot_nearest {0x10000000000001p0, 0x1p104} {0x0fffffffffffffp0, -1.0} = -1.0", line)
+        # broken test unrelated to interval airthmetic
+        command = "@test_broken $expr"
+    elseif occursin("atan2 [-0.0, 1.0]_com [-2.0, -0.1]_com = [0X1.ABA397C7259DDP+0, 0X1.921FB54442D19P+1]_dac", line)
+        # erroneous test: the decoration of the result should be `com`
+        command =
+            """
+            @warn "The original test `atan2 [-0.0, 1.0]_com [-2.0, -0.1]_com = [0X1.ABA397C7259DDP+0, 0X1.921FB54442D19P+1]_dac` is wrong and has been modified. The result should have the decoration `com`"
+                @test atan(interval(bareinterval(-0.0, 1.0), com), interval(bareinterval(-2.0, -0.1), com)) === interval(bareinterval(0x1.ABA397C7259DDP+0, 0x1.921FB54442D19P+1), com)"""
+    end
 
     command = haswarning ? "@test_logs (:warn,) $command" : command
 
@@ -238,7 +246,7 @@ end
 function parse_interval(ival::AbstractString, dec::Union{Nothing,AbstractString})
     ival == "nai" && return "nai(Interval{Float64})"
     if ival == "entire"
-        ival =  "entireinterval(BareInterval{Float64})"
+        ival = "entireinterval(BareInterval{Float64})"
     elseif ival == "empty"
         ival = "emptyinterval(BareInterval{Float64})"
     else
diff --git a/test/runtests.jl b/test/runtests.jl
index aabd85d91..1c5cf2d50 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -24,4 +24,4 @@ for f ∈ readdir("ITF1788_tests"; join = true)
     @testset "$f" begin
         include(f)
     end
-end
\ No newline at end of file
+end