Fixup equality

src/basic.jl

@@ -117,7 +117,7 @@ function Base.:(==)(a::MemoryView{T}, b::MemoryView{T}) where {T <: Bits}
     a.ref === b.ref && return true
     GC.@preserve a b begin
         aptr = Ptr{Nothing}(pointer(a))
-        bptr = Ptr{Nothing}(pointer(a))
+        bptr = Ptr{Nothing}(pointer(b))
         y = @ccall memcmp(aptr::Ptr{Nothing}, bptr::Ptr{Nothing}, length(a)::Int)::Cint
     end
     iszero(y)

test/runtests.jl

@@ -2,6 +2,8 @@ using Test
 using MemoryViews
 using Aqua
 
+MemoryViews.MemoryView(s::GenericString) = MemoryView(s.string)
+
 MUT_BACKINGS = Any[
     # Arrays
     UInt8[1, 2],
@@ -53,6 +55,10 @@ end
         @test m isa ImmutableMemoryView{UInt8}
         @test isempty(m)
     end
+
+    s = Test.GenericString("abγδf")
+    @test codeunits(s) == MemoryView(s)
+    @test codeunits(s[2:end-2]) == MemoryView(s)[2:end-1]
 end
 
 @testset "Immutable views are immutable" begin
@@ -83,10 +89,6 @@ end
     v = view(view(rand(UInt16, 19), 2:11), 3:9)
     mem = MemoryView(v)
     @test mem == v
-
-    s = SubString(Test.GenericString("dslkjad"), 2:5)
-    # This is not implemented
-    @test_throws Exception MemoryView(s)
 end
 
 memlen(x) = length(MemoryView(x))
@@ -301,6 +303,21 @@ end
     end
 end
 
+@testset "Equality" begin
+    v = rand(UInt, 10)
+    m1 = MemoryView(v)
+    m2 = MemoryView(copy(v))
+    @test m1 == m2
+    @test m1 !== m2
+
+    m2 = m2[1:end-1]
+    @test m1 != m2
+    m1 = m1[1:end-2]
+    @test m1 != m2
+    m2 = m2[1:end-1]
+    @test m1 == m2
+end
+
 @testset "MemoryKind" begin
     @test MemoryKind(Vector{Int16}) == IsMemory(MutableMemoryView{Int16})
     @test MemoryKind(typeof(codeunits(view("abc", 2:3)))) ==