Add tests for OffsetArrays

JuliaLang · Jul 10, 2020 · c96f9b5 · c96f9b5
1 parent 90e4b74
commit c96f9b5
Show file tree

Hide file tree

Showing 2 changed files with 16 additions and 2 deletions.
diff --git a/base/abstractarray.jl b/base/abstractarray.jl
@@ -362,7 +362,7 @@ julia> first(Bool[], 1)
 0-element Array{Bool,1}
 ```
 """
-first(v::AbstractVector, n::Integer) = @inbounds v[firstindex(v):min(firstindex(v) - 1 + n, end)]
+first(v::AbstractVector, n::Integer) = @inbounds v[firstindex(v):min(firstindex(v) + n - 1, end)]
 
 """
     last(coll)
@@ -401,7 +401,7 @@ julia> last(Float64[], 1)
 0-element Array{Float64,1}
 ```
 """
-last(v::AbstractArray, n::Integer) = @inbounds v[max(firstindex(v), end + 1 - n):end]
+last(v::AbstractArray, n::Integer) = @inbounds v[max(firstindex(v), end - n + 1):end]
 
 """
     strides(A)

diff --git a/test/offsetarray.jl b/test/offsetarray.jl
@@ -609,3 +609,17 @@ end
     @test_throws DimensionMismatch maximum!(fill(0, -4:-4, 7:7, -6:-5, 1:1), B)
     @test_throws DimensionMismatch minimum!(fill(0, -4:-4, 7:7, -6:-5, 1:1), B)
 end
+
+@testset "first/last n elements of vector" begin
+    f = firstindex(v)
+    @test first(v, -2) == []
+    @test first(v, 2) == v[f:f+1]
+    @test first(v, 100) == v0
+    @test first(v, 100) !== v
+    @test first(v, 1) != v[f]
+    @test last(v, -2) == []
+    @test last(v, 2) == v[end-1:end]
+    @test last(v, 100) == v0
+    @test last(v, 100) !== v
+    @test last(v, 1) != v[end]
+end