From 5238208a5af24303d21adbe80fe4e260695a7e31 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Wed, 22 Nov 2023 18:26:03 +0000
Subject: [PATCH 1/9] add `getproperty(x)`

---
 Project.toml  | 2 +-
 src/PTYQoL.jl | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/Project.toml b/Project.toml
index 9ef689f..a56d9bf 100644
--- a/Project.toml
+++ b/Project.toml
@@ -1,7 +1,7 @@
 name = "PTYQoL"
 uuid = "551ad714-b11a-4605-8871-12721def4e72"
 authors = ["Tianyi Pu <912396513@qq.com> and contributors"]
-version = "0.1.3"
+version = "0.1.4"
 
 [weakdeps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
diff --git a/src/PTYQoL.jl b/src/PTYQoL.jl
index 7387401..4c16e69 100644
--- a/src/PTYQoL.jl
+++ b/src/PTYQoL.jl
@@ -58,4 +58,7 @@ import Base: ==
 ==(f::Function, ::typeof(identity)) = isone(f)
 ==(::typeof(identity), f::Function) = isone(f)
 
+import Base: getproperty, Fix2
+getproperty(x) = Fix2(getproperty, x)
+
 end

From 865f56084c7b6a978b5e3c5426916b76bd0c5952 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Sun, 26 Nov 2023 08:15:33 +0000
Subject: [PATCH 2/9] partially solve
 https://github.com/JuliaArrays/InfiniteArrays.jl/issues/147

---
 Project.toml                   |  2 ++
 ext/PTYQoLInfiniteArraysExt.jl | 14 ++++++++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 ext/PTYQoLInfiniteArraysExt.jl

diff --git a/Project.toml b/Project.toml
index a56d9bf..2f6cf7b 100644
--- a/Project.toml
+++ b/Project.toml
@@ -10,6 +10,7 @@ ContinuumArrays = "7ae1f121-cc2c-504b-ac30-9b923412ae5c"
 IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 QuasiArrays = "c4ea9172-b204-11e9-377d-29865faadc5c"
 ClassicalOrthogonalPolynomials = "b30e2e7b-c4ee-47da-9d5f-2c5c27239acd"
+InfiniteArrays = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
 
 [extensions]
 PTYQoLLinearAlgebraExt = "LinearAlgebra"
@@ -18,6 +19,7 @@ PTYQoLContinuumArraysExt = "ContinuumArrays"
 PTYQoLIntervalSetsExt = "IntervalSets"
 PTYQoLQuasiArraysExt = "QuasiArrays"
 PTYQoLClassicalOrthogonalPolynomialsExt = "ClassicalOrthogonalPolynomials"
+PTYQoLInfiniteArraysExt = "InfiniteArrays"
 
 [compat]
 julia = "1"
diff --git a/ext/PTYQoLInfiniteArraysExt.jl b/ext/PTYQoLInfiniteArraysExt.jl
new file mode 100644
index 0000000..d974655
--- /dev/null
+++ b/ext/PTYQoLInfiniteArraysExt.jl
@@ -0,0 +1,14 @@
+module PTYQoLInfiniteArraysExt
+
+import InfiniteArrays: InfStepRange, AbstractInfUnitRange, Zeros, ∞, diag, Diagonal
+#import LinearAlgebra: diag, Diagonal
+
+infdiag(a, k) = iszero(k) ? copy(a.diag) : zero(a.diag)
+
+for TYP in (InfStepRange, AbstractInfUnitRange)
+    @eval begin
+        diag(a::Diagonal{T, <:$TYP}, k::Integer=0) where T = infdiag(a, k)
+    end
+end
+
+end
\ No newline at end of file

From 6046ac23f39d9f3b032485f4386a7975c276a75c Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Sun, 26 Nov 2023 08:16:31 +0000
Subject: [PATCH 3/9] support `getindex` and `setindex!` for
 `AbstractBandedMatrix`

---
 Project.toml                   |  2 ++
 ext/PTYQoLBandedMatricesExt.jl | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 ext/PTYQoLBandedMatricesExt.jl

diff --git a/Project.toml b/Project.toml
index 2f6cf7b..b4014da 100644
--- a/Project.toml
+++ b/Project.toml
@@ -11,6 +11,7 @@ IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
 QuasiArrays = "c4ea9172-b204-11e9-377d-29865faadc5c"
 ClassicalOrthogonalPolynomials = "b30e2e7b-c4ee-47da-9d5f-2c5c27239acd"
 InfiniteArrays = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
+BandedMatrices = "aae01518-5342-5314-be14-df237901396f"
 
 [extensions]
 PTYQoLLinearAlgebraExt = "LinearAlgebra"
@@ -20,6 +21,7 @@ PTYQoLIntervalSetsExt = "IntervalSets"
 PTYQoLQuasiArraysExt = "QuasiArrays"
 PTYQoLClassicalOrthogonalPolynomialsExt = "ClassicalOrthogonalPolynomials"
 PTYQoLInfiniteArraysExt = "InfiniteArrays"
+PTYQoLBandedMatricesExt = "BandedMatrices"
 
 [compat]
 julia = "1"
diff --git a/ext/PTYQoLBandedMatricesExt.jl b/ext/PTYQoLBandedMatricesExt.jl
new file mode 100644
index 0000000..df36168
--- /dev/null
+++ b/ext/PTYQoLBandedMatricesExt.jl
@@ -0,0 +1,28 @@
+module PTYQoLBandedMatricesExt
+
+import BandedMatrices: inbands_getindex, inbands_setindex!, AbstractBandedMatrix, bandwidths, MemoryLayout, BandedLayout
+import Base: getindex, setindex!, @propagate_inbounds
+
+@propagate_inbounds function getindex(A::AbstractBandedMatrix, j::Integer, k::Integer)
+    @boundscheck checkbounds(A, j, k)
+    l, u = bandwidths(A)
+    if -l ≤ k-j ≤ u
+        inbands_getindex(A, j, k)
+    else
+        zero(eltype(A))
+    end
+end
+
+@propagate_inbounds function setindex!(A::AbstractBandedMatrix, v, j::Integer, k::Integer)
+    @boundscheck checkbounds(A, j, k)
+    l, u = bandwidths(A)
+    if -l ≤ k-j ≤ u
+        inbands_setindex!(A, v, j, k)
+    elseif iszero(v)
+        zero(eltype(A))
+    else
+        error("out of band.")
+    end
+end
+
+end
\ No newline at end of file

From 4c3fbe28bfb55625547bfa1dcd40a9c57ad527b8 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Sun, 26 Nov 2023 08:16:55 +0000
Subject: [PATCH 4/9] support `MemoryLayout` for `AbstractBandedMatrix`

---
 ext/PTYQoLBandedMatricesExt.jl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ext/PTYQoLBandedMatricesExt.jl b/ext/PTYQoLBandedMatricesExt.jl
index df36168..1486da1 100644
--- a/ext/PTYQoLBandedMatricesExt.jl
+++ b/ext/PTYQoLBandedMatricesExt.jl
@@ -3,6 +3,8 @@ module PTYQoLBandedMatricesExt
 import BandedMatrices: inbands_getindex, inbands_setindex!, AbstractBandedMatrix, bandwidths, MemoryLayout, BandedLayout
 import Base: getindex, setindex!, @propagate_inbounds
 
+MemoryLayout(::Type{<:AbstractBandedMatrix}) = BandedLayout()
+
 @propagate_inbounds function getindex(A::AbstractBandedMatrix, j::Integer, k::Integer)
     @boundscheck checkbounds(A, j, k)
     l, u = bandwidths(A)

From 6a63fde158b480f9eb4f159e8e9575ed6274665a Mon Sep 17 00:00:00 2001
From: Tianyi Pu <44583944+putianyi889@users.noreply.github.com>
Date: Sun, 26 Nov 2023 08:30:16 +0000
Subject: [PATCH 5/9] try to add integration tests

---
 .github/workflows/Downstream.yml | 76 ++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 .github/workflows/Downstream.yml

diff --git a/.github/workflows/Downstream.yml b/.github/workflows/Downstream.yml
new file mode 100644
index 0000000..4b15cde
--- /dev/null
+++ b/.github/workflows/Downstream.yml
@@ -0,0 +1,76 @@
+name: Compatibility
+on:
+  push:
+    branches: [master]
+  pull_request:
+    paths-ignore:
+      - 'LICENSE'
+      - 'README.md'
+      - '.github/workflows/TagBot.yml'
+
+concurrency:
+  group: build-${{ github.event.pull_request.number || github.ref }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+jobs:
+  pre_job:
+    # continue-on-error: true # Uncomment once integration is finished
+    runs-on: ubuntu-latest
+    # Map a step output to a job output
+    outputs:
+      should_skip: ${{ steps.skip_check.outputs.should_skip }}
+    steps:
+      - id: skip_check
+        uses: fkirc/skip-duplicate-actions@v5
+  test:
+    needs: pre_job
+    if: needs.pre_job.outputs.should_skip != 'true'
+    name: ${{ matrix.package.group }}/${{ matrix.package.repo }}/${{ matrix.julia-version }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: true
+      matrix:
+        julia-version: ['1']
+        os: [ubuntu-latest]
+        package:
+          - {repo: BandedMatrices.jl, group: JuliaLinearAlgebra}
+          - {repo: CircularArrays.jl, group: Vexatos}
+          - {repo: ClassicalOrthogonalPolynomials.jl, group: JuliaApproximation}
+          - {repo: ContinuumArrays.jl, group: JuliaApproximation}
+          - {repo: InfiniteArrays.jl, group: JuliaArrays}
+          - {repo: IntervalSets.jl, group: JuliaMath}
+          - {repo: QuasiArrays.jl, group: JuliaApproximation}
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: julia-actions/setup-julia@v1
+        with:
+          version: ${{ matrix.julia-version }}
+          arch: x64
+      - uses: julia-actions/julia-buildpkg@latest
+      - name: Clone Downstream
+        uses: actions/checkout@v4
+        with:
+          repository: ${{ matrix.package.group }}/${{ matrix.package.repo }}
+          path: downstream
+      - name: Load this and run the downstream tests
+        shell: julia --color=yes --project=downstream {0}
+        run: |
+          using Pkg
+          try
+            # force it to use this PR's version of the package
+            Pkg.develop(PackageSpec(path="."))  # resolver may fail with main deps
+            Pkg.update()
+            Pkg.test(; coverage = true)  # resolver may fail with test time deps
+          catch err
+            err isa Pkg.Resolve.ResolverError || rethrow()
+            # If we can't resolve that means this is incompatible by SemVer and this is fine
+            # It means we marked this as a breaking change, so we don't need to worry about
+            # Mistakenly introducing a breaking change, as we have intentionally made one
+            @info "Not compatible with this release. No problem." exception=err
+            exit(0)  # Exit immediately, as a success
+          end
+      - uses: julia-actions/julia-processcoverage@v1
+      - uses: codecov/codecov-action@v3
+        with:
+          files: lcov.info

From c2223efd8e2600f24dfecf01072d8a83f4a068d3 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Mon, 27 Nov 2023 08:55:34 +0000
Subject: [PATCH 6/9] https://github.com/JuliaLang/julia/pull/52312

---
 src/PTYQoL.jl | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/PTYQoL.jl b/src/PTYQoL.jl
index 4c16e69..364996a 100644
--- a/src/PTYQoL.jl
+++ b/src/PTYQoL.jl
@@ -61,4 +61,13 @@ import Base: ==
 import Base: getproperty, Fix2
 getproperty(x) = Fix2(getproperty, x)
 
+# https://github.com/JuliaLang/julia/pull/52312
+import Base: first, last, lastindex, front, tail, getindex
+first(A::CartesianIndex) = first(Tuple(A))
+last(A::CartesianIndex) = last(Tuple(A))
+lastindex(A::CartesianIndex) = lastindex(Tuple(A))
+front(A::CartesianIndex) = CartesianIndex(front(Tuple(A)))
+tail(A::CartesianIndex) = CartesianIndex(tail(Tuple(A)))
+getindex(A::CartesianIndex, i) = CartesianIndex(Tuple(A)[i])
+
 end

From 33a02a53b913fe6d2f4ab5c7c66bdeee1fc554a7 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Mon, 27 Nov 2023 09:14:18 +0000
Subject: [PATCH 7/9] 
 https://github.com/JuliaLinearAlgebra/ArrayLayouts.jl/pull/184

---
 Project.toml                 | 2 ++
 ext/PTYQoLArrayLayoutsExt.jl | 8 ++++++++
 2 files changed, 10 insertions(+)
 create mode 100644 ext/PTYQoLArrayLayoutsExt.jl

diff --git a/Project.toml b/Project.toml
index b4014da..b58670e 100644
--- a/Project.toml
+++ b/Project.toml
@@ -12,6 +12,7 @@ QuasiArrays = "c4ea9172-b204-11e9-377d-29865faadc5c"
 ClassicalOrthogonalPolynomials = "b30e2e7b-c4ee-47da-9d5f-2c5c27239acd"
 InfiniteArrays = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
 BandedMatrices = "aae01518-5342-5314-be14-df237901396f"
+ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 
 [extensions]
 PTYQoLLinearAlgebraExt = "LinearAlgebra"
@@ -22,6 +23,7 @@ PTYQoLQuasiArraysExt = "QuasiArrays"
 PTYQoLClassicalOrthogonalPolynomialsExt = "ClassicalOrthogonalPolynomials"
 PTYQoLInfiniteArraysExt = "InfiniteArrays"
 PTYQoLBandedMatricesExt = "BandedMatrices"
+PTYQoLArrayLayoutsExt = "ArrayLayouts"
 
 [compat]
 julia = "1"
diff --git a/ext/PTYQoLArrayLayoutsExt.jl b/ext/PTYQoLArrayLayoutsExt.jl
new file mode 100644
index 0000000..9c28c54
--- /dev/null
+++ b/ext/PTYQoLArrayLayoutsExt.jl
@@ -0,0 +1,8 @@
+module PTYQoLArrayLayoutsExt
+
+import ArrayLayouts: rowsupport, colsupport
+
+rowsupport(A, i::CartesianIndex{2}) = rowsupport(A, first(i))
+colsupport(A, i::CartesianIndex{2}) = colsupport(A, last(i))
+
+end
\ No newline at end of file

From 9df379da203f305477d6cc29311bd1cb9b9589a3 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Mon, 27 Nov 2023 09:23:45 +0000
Subject: [PATCH 8/9] Update PTYQoLArrayLayoutsExt.jl

---
 ext/PTYQoLArrayLayoutsExt.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ext/PTYQoLArrayLayoutsExt.jl b/ext/PTYQoLArrayLayoutsExt.jl
index 9c28c54..16a8876 100644
--- a/ext/PTYQoLArrayLayoutsExt.jl
+++ b/ext/PTYQoLArrayLayoutsExt.jl
@@ -1,5 +1,6 @@
 module PTYQoLArrayLayoutsExt
 
+# https://github.com/JuliaLinearAlgebra/ArrayLayouts.jl/pull/184
 import ArrayLayouts: rowsupport, colsupport
 
 rowsupport(A, i::CartesianIndex{2}) = rowsupport(A, first(i))

From f98ff15e3974736d5f2a011dc1815d868575e4f0 Mon Sep 17 00:00:00 2001
From: Tianyi Pu <912396513@qq.com>
Date: Mon, 27 Nov 2023 13:52:40 +0000
Subject: [PATCH 9/9] coverage

---
 Project.toml                   |   4 +-
 ext/PTYQoLBandedMatricesExt.jl |   2 +
 ext/PTYQoLInfiniteArraysExt.jl |   2 +-
 test/runtests.jl               | 123 ++++++++++++++++++++-------------
 4 files changed, 81 insertions(+), 50 deletions(-)

diff --git a/Project.toml b/Project.toml
index b58670e..b6dc571 100644
--- a/Project.toml
+++ b/Project.toml
@@ -35,6 +35,8 @@ DomainSets = "5b8099bc-c8ec-5219-889f-1d9e522a28bf"
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 ClassicalOrthogonalPolynomials = "b30e2e7b-c4ee-47da-9d5f-2c5c27239acd"
+InfiniteArrays = "4858937d-0d70-526a-a4dd-2d5cb5dd786c"
+ArrayLayouts = "4c555306-a7a7-4459-81d9-ec55ddd5c99a"
 
 [targets]
-test = ["Test", "LinearAlgebra", "Documenter", "DomainSets", "ContinuumArrays", "ClassicalOrthogonalPolynomials"]
+test = ["Test", "LinearAlgebra", "Documenter", "DomainSets", "ContinuumArrays", "ClassicalOrthogonalPolynomials", "InfiniteArrays", "ArrayLayouts"]
diff --git a/ext/PTYQoLBandedMatricesExt.jl b/ext/PTYQoLBandedMatricesExt.jl
index 1486da1..25cc0ba 100644
--- a/ext/PTYQoLBandedMatricesExt.jl
+++ b/ext/PTYQoLBandedMatricesExt.jl
@@ -3,6 +3,8 @@ module PTYQoLBandedMatricesExt
 import BandedMatrices: inbands_getindex, inbands_setindex!, AbstractBandedMatrix, bandwidths, MemoryLayout, BandedLayout
 import Base: getindex, setindex!, @propagate_inbounds
 
+# too tedious to test
+
 MemoryLayout(::Type{<:AbstractBandedMatrix}) = BandedLayout()
 
 @propagate_inbounds function getindex(A::AbstractBandedMatrix, j::Integer, k::Integer)
diff --git a/ext/PTYQoLInfiniteArraysExt.jl b/ext/PTYQoLInfiniteArraysExt.jl
index d974655..cd0079f 100644
--- a/ext/PTYQoLInfiniteArraysExt.jl
+++ b/ext/PTYQoLInfiniteArraysExt.jl
@@ -3,7 +3,7 @@ module PTYQoLInfiniteArraysExt
 import InfiniteArrays: InfStepRange, AbstractInfUnitRange, Zeros, ∞, diag, Diagonal
 #import LinearAlgebra: diag, Diagonal
 
-infdiag(a, k) = iszero(k) ? copy(a.diag) : zero(a.diag)
+infdiag(a, k) = iszero(k) ? copy(a.diag) : Zeros{eltype(a)}(∞)
 
 for TYP in (InfStepRange, AbstractInfUnitRange)
     @eval begin
diff --git a/test/runtests.jl b/test/runtests.jl
index a5608dd..6e68173 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,63 +1,77 @@
 using PTYQoL
 using Test, Documenter
 
-@testset "//" begin
-    @test 1 // 2 isa Rational
-    @test 1.0 // 2.0 == 1 // 2
-end
-
-@testset "dotu" begin
-    using LinearAlgebra
-    u = rand(10); v = rand(10)
-    @test LinearAlgebra.BLAS.dotu(u, v) == LinearAlgebra.BLAS.dotu(u, 1, v, 1) == LinearAlgebra.BLAS.dotu(10, u, 1, v, 1) ≈ u ⋅ v
-
-    u = rand(ComplexF64, 10); v = rand(ComplexF64, 10)
-    @test endswith(string(which(LinearAlgebra.BLAS.dotu, map(typeof,(10,u,1,v,1))).file), "blas.jl")
-    @test LinearAlgebra.BLAS.dotu(u, v) == LinearAlgebra.BLAS.dotu(u, 1, v, 1) == LinearAlgebra.BLAS.dotu(10, u, 1, v, 1)
-end
-
-@testset "eps ceil floor" begin
-    @test eps(ComplexF64) == eps(Float64)
-    @test ceil(0.5+0.5im) == 1+1im == floor(1.5+1.5im)
+@testset "Pull Requests" begin
+    @testset "https://github.com/JuliaLang/julia/issues/35033" begin
+        @test startswith(AbstractArray, "Abstract")
+        @test endswith(AbstractArray, Array)
+    end
+    
+    @testset "https://github.com/JuliaLang/julia/pull/48894" begin
+        @test AbstractRange{Float64}(1:10) ≡ AbstractVector{Float64}(1:10) ≡ AbstractArray{Float64}(1:10) ≡ 1.0:10
+    end
+    
+    @testset "https://github.com/JuliaLang/julia/pull/52312" begin
+        using Base: front, tail
+        ind = CartesianIndex(1,2,3)
+        @test first(ind) == 1
+        @test last(ind) == ind[end] == 3
+        @test front(ind) == ind[1:end-1] == CartesianIndex(1,2)
+        @test tail(ind) == ind[2:end] == CartesianIndex(2,3)
+    end
 end
 
-@testset "front tail" begin
-    using Base: front, tail
-    @test front(1:10) == 1:9 == tail(0:9)
-end
+@testset "Misc" begin
+    @testset "//" begin
+        @test 1 // 2 isa Rational
+        @test 1.0 // 2.0 == 1 // 2
+    end
 
-@testset "https://github.com/JuliaLang/julia/issues/35033" begin
-    @test startswith(AbstractArray, "Abstract")
-    @test endswith(AbstractArray, Array)
-end
+    @testset "dotu" begin
+        using LinearAlgebra
+        u = rand(10); v = rand(10)
+        @test LinearAlgebra.BLAS.dotu(u, v) == LinearAlgebra.BLAS.dotu(u, 1, v, 1) == LinearAlgebra.BLAS.dotu(10, u, 1, v, 1) ≈ u ⋅ v
 
-@testset "https://github.com/JuliaLang/julia/pull/48894" begin
-    @test AbstractRange{Float64}(1:10) ≡ AbstractVector{Float64}(1:10) ≡ AbstractArray{Float64}(1:10) ≡ 1.0:10
-end
+        u = rand(ComplexF64, 10); v = rand(ComplexF64, 10)
+        @test endswith(string(which(LinearAlgebra.BLAS.dotu, map(typeof,(10,u,1,v,1))).file), "blas.jl")
+        @test LinearAlgebra.BLAS.dotu(u, v) == LinearAlgebra.BLAS.dotu(u, 1, v, 1) == LinearAlgebra.BLAS.dotu(10, u, 1, v, 1)
+    end
 
-@testset "Function interface" begin
-    using Base: Fix2
-    @test identity ∘ identity ≡ identity ≡ exp10 ∘ inv(exp10) ≡ log2 ∘ inv(log2) ≡ inv(identity)
-    @test identity ∘ exp ≡ exp ≡ exp ∘ identity
-    @test abs ∘ abs ≡ abs
-    @test inv(exp10 ∘ exp2) ≡ log2 ∘ log10
-    @test Fix2(+, 0) == identity == Fix2(*, 1)
+    @testset "eps ceil floor" begin
+        @test eps(ComplexF64) == eps(Float64)
+        @test ceil(0.5+0.5im) == 1+1im == floor(1.5+1.5im)
+    end
 
-    @test Fix2(+, 1) ∘ Fix2(+, 2) == Fix2(+, 3)
-    @test Fix2(*, 2) ∘ Fix2(*, 3) == Fix2(*, 6)
-    @test Fix2(+, 3) ^ 5 == Fix2(+, 15)
-    @test Fix2(*, 4) ^ 3 == Fix2(*, 64)
-    @test Fix2(^, 2) ∘ Fix2(^, 3) == Fix2(^, 6)
-end
+    @testset "front tail" begin
+        using Base: front, tail
+        @test front(1:10) == 1:9 == tail(0:9)
+    end
 
-@testset "ln" begin
-    @test ln(1) == 0 # just for coverage
+    @testset "Function interface" begin
+        using Base: Fix2
+        @test identity ∘ identity ≡ identity ≡ exp10 ∘ inv(exp10) ≡ log2 ∘ inv(log2) ≡ inv(identity)
+        @test identity ∘ exp ≡ exp ≡ exp ∘ identity
+        @test abs ∘ abs ≡ abs
+        @test inv(exp10 ∘ exp2) ≡ log2 ∘ log10
+        @test Fix2(+, 0) == identity == Fix2(*, 1)
+    
+        @test Fix2(+, 1) ∘ Fix2(+, 2) == Fix2(+, 3)
+        @test Fix2(*, 2) ∘ Fix2(*, 3) == Fix2(*, 6)
+        @test Fix2(+, 3) ^ 5 == Fix2(+, 15)
+        @test Fix2(*, 4) ^ 3 == Fix2(*, 64)
+        @test Fix2(^, 2) ∘ Fix2(^, 3) == Fix2(^, 6)
+    end
 end
 
-@testset "precision_convert" begin
-    setprecision(256)
-    x = precision_convert(BigFloat, BigFloat(1), 128)
-    @test precision(x) == 128
+@testset "Utils" begin
+    @testset "ln" begin
+        @test ln(1) == 0 # just for coverage
+    end
+    @testset "precision_convert" begin
+        setprecision(256)
+        x = precision_convert(BigFloat, BigFloat(1), 128)
+        @test precision(x) == 128
+    end
 end
 
 @testset "Extensions" begin
@@ -79,6 +93,19 @@ end
         @test AbstractJacobi{BigFloat}(Legendre()) isa Legendre{BigFloat}
         @test AbstractJacobi{Float32}(Ultraspherical(2)) isa Ultraspherical{Float32}
     end
+    @testset "InfiniteArrays" begin
+        using InfiniteArrays
+        D = Diagonal(1:∞)
+        @test diag(D) == 1:∞
+        @test diag(D, 1) == Zeros(∞)
+    end
+    @testset "ArrayLayouts" begin
+        using ArrayLayouts
+        A = rand(3,5)
+        ind = CartesianIndex(2,3)
+        @test rowsupport(A, ind) == rowsupport(A,2)
+        @test colsupport(A, ind) == colsupport(A,3)
+    end
 end
 
 DocMeta.setdocmeta!(PTYQoL, :DocTestSetup, :(using PTYQoL); recursive=true)