Implement AquaCrop cropcover(), cropyield()

src/crop/aquacrop.jl

@@ -27,9 +27,9 @@ end
 
 croptype(cs::AquaCropState) = cs.croptype
 cropname(cs::AquaCropState) = cropname(croptype(cs))
-cropheight(cs::AquaCropState) = cs.height
-cropcover(cs::AquaCropState) = 0.0  # TODO: implement
-cropyield(cs::AquaCropState) = 0.0  # TODO: implement, units?
+cropheight(cs::AquaCropState) = cs.height  # TODO: use AquaCrop state info
+cropcover(cs::AquaCropState) = AquaCrop.canopycover(cs.cropstate)
+cropyield(cs::AquaCropState) = AquaCrop.dryyield(cs.cropstate)  # TODO: there is also freshyield
 isharvestable(cs::AquaCropState) = true  # TODO: implement this correctly
 
 """

test/crop_tests.jl

@@ -65,6 +65,6 @@ end
     @test cropname(fp) isa String
     @test cropheight(fp) isa Length{Float64}
     @test cropcover(fp) isa Float64
-    @test cropyield(fp) isa Float64
+    @test cropyield(fp) isa type(1.0u"kg/ha")
     # TODO: test stepagent!(), sow!(), harvest!()
 end