test fallbacks

base/io.jl

@@ -524,7 +524,7 @@ julia> rm("my_file.txt")
 readuntil(filename::AbstractString, delim; kw...) = open(io->readuntil(io, delim; kw...), convert(String, filename)::String)
 readuntil(stream::IO, delim::UInt8; kw...) = _unsafe_take!(copyuntil(IOBuffer(sizehint=70), stream, delim; kw...))
 readuntil(stream::IO, delim::Union{AbstractChar, AbstractString}; kw...) = String(_unsafe_take!(copyuntil(IOBuffer(sizehint=70), stream, delim; kw...)))
-readuntil(stream::IO, delim::T; keep::Bool=false) where T = _copyuntil(Vector{T}(), s, delim, keep)
+readuntil(stream::IO, delim::T; keep::Bool=false) where T = _copyuntil(Vector{T}(), stream, delim, keep)
 
 
 """

test/read.jl

@@ -677,6 +677,21 @@ end
     @test  isempty(itr) # now it is empty
 end
 
+@testset "readuntil/copyuntil fallbacks" begin
+    # test fallback for generic delim::T
+    buf = IOBuffer()
+    fib = [1,1,2,3,5,8,13,21]
+    write(buf, fib)
+    @test readuntil(seekstart(buf), 21) == fib[1:end-1]
+    @test readuntil(buf, 21) == Int[]
+    @test readuntil(seekstart(buf), 21; keep=true) == fib
+    out = IOBuffer()
+    @test copyuntil(out, seekstart(buf), 21) === out
+    @test reinterpret(Int, take!(out)) == fib[1:end-1]
+    @test copyuntil(out, seekstart(buf), 21; keep=true) === out
+    @test reinterpret(Int, take!(out)) == fib
+end
+
 # more tests for reverse(eachline)
 @testset "reverse(eachline)" begin
     lines = vcat(repr.(1:4), ' '^50000 .* repr.(5:10), repr.(11:10^5))