Fix behavior of one(::Quantity)

Author: MilesCranmer

src/utils.jl

@@ -51,7 +51,7 @@ Base.one(::Type{Quantity{T}}) where {T} = one(Quantity{T,DEFAULT_DIM_TYPE})
 Base.one(::Type{Quantity}) = one(Quantity{DEFAULT_VALUE_TYPE})
 Base.one(::Type{Dimensions{R}}) where {R} = Dimensions{R}()
 Base.one(::Type{Dimensions}) = one(Dimensions{DEFAULT_DIM_TYPE})
-Base.one(q::Quantity) = one(typeof(q))
+Base.one(q::Quantity) = Quantity(one(ustrip(q)), dimension(q))
 Base.one(d::Dimensions) = one(typeof(d))
 
 # Additive identities:

test/unittests.jl

@@ -200,6 +200,7 @@ end
     @test one(Dimensions()) == Dimensions()
     @test typeof(one(Quantity)) == Quantity{DEFAULT_VALUE_TYPE,DEFAULT_DIM_TYPE}
     @test ustrip(one(Quantity)) === one(DEFAULT_VALUE_TYPE)
+    @test typeof(one(Quantity(ones(32, 32)))) == Quantity{Matrix{Float64},DEFAULT_DIM_TYPE}
 
     x = Quantity(1, length=1)