Backport: Promote rangespace/domainspace of Conversion (#539)

* Backport: Promote rangespace/domainspace of Conversion

* Tests for Conversion space promotion

Author: jishnub

Project.toml

@@ -1,6 +1,6 @@
 name = "ApproxFunBase"
 uuid = "fbd15aa5-315a-5a7d-a8a4-24992e37be05"
-version = "0.8.49"
+version = "0.8.50"
 
 [deps]
 AbstractFFTs = "621f4979-c628-5d54-868e-fcf4e3e8185c"

src/Operators/banded/Conversion.jl

@@ -27,7 +27,8 @@ end
 domainspace(C::ConcreteConversion)=C.domainspace
 rangespace(C::ConcreteConversion)=C.rangespace
 
-
+promotedomainspace(C::Conversion, sp::Space) = Conversion(sp, rangespace(C))
+promoterangespace(C::Conversion, sp::Space) = Conversion(domainspace(C), sp)
 
 function _implementconversionerror(a, b)
     error("Implement Conversion from ", typeof(a), " to ", typeof(b))

test/runtests.jl

@@ -471,6 +471,9 @@ end
         M = Multiplication(Fun(PointSpace(1:4)), PointSpace(1:4))
         M2 = @inferred C * M * C
         @test M2 * f ≈ M * f
+
+        @test @inferred(C : PointSpace(1:4)) == C
+        @test @inferred(C → PointSpace(1:4)) == C
     end
     @testset "ConstantOperator" begin
         C = ConstantOperator(3.0, PointSpace(1:4))