Add tests for convert

Author: jishnub

test/bidiag.jl

@@ -1158,4 +1158,15 @@ end
     @test opnorm(B, Inf) == opnorm(Matrix(B), Inf)
 end
 
+@testset "convert to Bidiagonal" begin
+    M = diagm(0 => [1,2,3], 1=>[4,5])
+    B = convert(Bidiagonal, M)
+    @test B == Bidiagonal(M, :U)
+    M = diagm(0 => [1,2,3], -1=>[4,5])
+    B = convert(Bidiagonal, M)
+    @test B == Bidiagonal(M, :L)
+    M = diagm(-1 => [1,2], 1=>[4,5])
+    @test_throws InexactError convert(Bidiagonal, M)
+end
+
 end # module TestBidiagonal

test/tridiag.jl

@@ -1099,4 +1099,26 @@ end
     @test opnorm(S, Inf) == opnorm(Matrix(S), Inf)
 end
 
+@testset "convert to Tridiagonal/SymTridiagonal" begin
+    @testset "Tridiagonal" begin
+        for M in [diagm(0 => [1,2,3], 1=>[4,5]),
+                diagm(0 => [1,2,3], 1=>[4,5], -1=>[6,7]),
+                diagm(-1 => [1,2], 1=>[4,5])]
+            B = convert(Tridiagonal, M)
+            @test B == Tridiagonal(M)
+        end
+        @test_throws InexactError convert(Tridiagonal, fill(5, 4, 4))
+    end
+    @testset "SymTridiagonal" begin
+        for M in [diagm(0 => [1,2,3], 1=>[4,5], -1=>[4,5]),
+            diagm(0 => [1,2,3]),
+            diagm(-1 => [1,2], 1=>[1,2])]
+            B = convert(SymTridiagonal, M)
+            @test B == SymTridiagonal(M)
+        end
+        @test_throws InexactError convert(SymTridiagonal, fill(5, 4, 4))
+        @test_throws InexactError convert(SymTridiagonal, diagm(0=>fill(NaN,4)))
+    end
+end
+
 end # module TestTridiagonal