Fix the implementation of the 'Haversine' distance (#860)

Author: eliascarv

src/distances.jl

@@ -55,7 +55,8 @@ end
 
 function evaluate(d::Haversine, p₁::Point{Dim,<:LatLon}, p₂::Point{Dim,<:LatLon}) where {Dim}
   uᵣ = unit(d.radius)
-  u = uᵣ === NoUnits ? u"m" : uᵣ
+  # add default unit if necessary
+  u = uᵣ === NoUnits ? u"m" : NoUnits
   latlon₁ = coords(p₁)
   latlon₂ = coords(p₂)
   v₁ = SVector(latlon₁.lon, latlon₁.lat)

test/distances.jl

@@ -32,6 +32,10 @@
   p4 = Point(cart2)
   @test evaluate(Haversine(), p1, p2) ≈ T(111194.92664455874) * u"m"
   @test evaluate(Haversine(), p3, p4) ≈ T(111194.92664455874) * u"m"
+  @test evaluate(Haversine(6371000u"m"), p1, p2) ≈ T(111194.92664455874) * u"m"
+  @test evaluate(Haversine(6371000u"m"), p3, p4) ≈ T(111194.92664455874) * u"m"
+  @test evaluate(Haversine(6371u"km"), p1, p2) ≈ T(111.19492664455874) * u"km"
+  @test evaluate(Haversine(6371u"km"), p3, p4) ≈ T(111.19492664455874) * u"km"
   @test evaluate(SphericalAngle(), p1, p2) ≈ deg2rad(T(1) * u"°")
   @test evaluate(SphericalAngle(), p3, p4) ≈ deg2rad(T(1) * u"°")
 end