diff --git a/src/ticks.jl b/src/ticks.jl
index 19e899a..1236dbf 100644
--- a/src/ticks.jl
+++ b/src/ticks.jl
@@ -36,25 +36,27 @@ function postdecimal_digits(x::T) where {T}
     return 0
 end
 
-fallback_ticks(x_min::T, x_max::T, k_min, k_max) where {T} = (
+function fallback_ticks(x_min::T, x_max::T, k_min, k_max, strict_span) where {T}
+    if !strict_span && x_min ≈ x_max
+        x_min, x_max = prevfloat(x_min), nextfloat(x_max)
+    end
     if k_min != 2 && isfinite(x_min) && isfinite(x_max)
         collect(T, range(x_min, x_max; length = k_min)), x_min, x_max
     else
         T[x_min, x_max], x_min, x_max
     end
-)
+end
 
 # Empty catchall
 optimize_ticks() = Any[]
 
 """
-    optimize_ticks(xmin, xmax; extend_ticks::Bool=false,
-                           Q=[(1.0,1.0), (5.0, 0.9), (2.0, 0.7), (2.5, 0.5), (3.0, 0.2)],
-                           k_min::Int=2, k_max::Int=10, k_ideal::Int=5,
-                           granularity_weight::Float64=1/4, simplicity_weight::Float64=1/6,
-                           coverage_weight::Float64=1/3, niceness_weight::Float64=1/4,
-                           strict_span=true, span_buffer = nothing
-        )
+optimize_ticks(xmin, xmax; extend_ticks::Bool = false,
+               Q = [(1.0,1.0), (5.0, 0.9), (2.0, 0.7), (2.5, 0.5), (3.0, 0.2)],
+               k_min = 2, k_max = 10, k_ideal = 5,
+               granularity_weight = 1/4, simplicity_weight = 1/6,
+               coverage_weight = 1/3, niceness_weight = 1/4,
+               strict_span = true, span_buffer = nothing)
 
 Find some reasonable values for tick marks.
 
@@ -152,11 +154,9 @@ function optimize_ticks(
     span_buffer = nothing,
     scale = nothing,
 ) where {T}
-    F = float(T)
-    if x_max - x_min < eps(F)
-        return fallback_ticks(x_min, x_max, k_min, k_max)
-    end
+    x_min ≈ x_max && return fallback_ticks(x_min, x_max, k_min, k_max, strict_span)
 
+    F = float(T)
     Qv = F[q[1] for q in Q]
     Qs = F[q[2] for q in Q]
 
@@ -190,7 +190,7 @@ function optimize_ticks(
             if sspan
                 @warn "No strict ticks found"
             else
-                return fallback_ticks(x_min, x_max, k_min, k_max)
+                return fallback_ticks(x_min, x_max, k_min, k_max, strict_span)
             end
         else
             return best, min_best, max_best
diff --git a/test/downstream.jl b/test/downstream.jl
index d62a747..b23d022 100644
--- a/test/downstream.jl
+++ b/test/downstream.jl
@@ -1,47 +1,90 @@
-using Pkg, PlotUtils
+using Pkg, PlotUtils, Test
 
 LibGit2 = Pkg.GitTools.LibGit2
 TOML = Pkg.TOML
 
-Plots_jl = joinpath(mkpath(tempname()), "Plots.jl")
-Plots_toml = joinpath(Plots_jl, "Project.toml")
-
-# clone and checkout the latest stable version of Plots
-depot = joinpath(first(DEPOT_PATH), "registries", "General", "P", "Plots", "Versions.toml")
-stable = maximum(VersionNumber.(keys(TOML.parse(read(depot, String)))))
-for i in 1:6
-    try
-        global repo = Pkg.GitTools.ensure_clone(
-            stdout,
-            Plots_jl,
-            "https://github.com/JuliaPlots/Plots.jl",
-        )
-        break
-    catch err
-        @warn err
-        sleep(20i)
+failsafe_clone_checkout(versions, path, url) = begin
+    local repo
+    for i in 1:6
+        try
+            repo = Pkg.GitTools.ensure_clone(
+                stdout,
+                path,
+                url,
+            )
+            break
+        catch err
+            @warn err
+            sleep(20i)
+        end
     end
+
+    @assert isfile(joinpath(path, "Project.toml")) "spurious network error: clone failed, bailing out"
+    stable = maximum(VersionNumber.(keys(TOML.parse(read(versions, String)))))
+    tag = LibGit2.GitObject(repo, "v$stable")
+    hash = string(LibGit2.target(tag))
+    LibGit2.checkout!(repo, hash)
+    nothing
+end
+
+fake_supported_version!(path) = begin
+    toml = joinpath(path, "Project.toml")
+    # fake the supported PlotUtils version for testing (for `Pkg.develop`)
+    PlotUtils_version = Pkg.Types.read_package(normpath(@__DIR__, "..", "Project.toml")).version
+    parsed_toml = TOML.parse(read(toml, String))
+    parsed_toml["compat"]["PlotUtils"] = string(PlotUtils_version)
+    open(toml, "w") do io
+        TOML.print(io, parsed_toml)
+    end
+    nothing
 end
-@assert isfile(Plots_toml) "spurious network error: clone failed, bailing out"
-tag = LibGit2.GitObject(repo, "v$stable")
-hash = string(LibGit2.target(tag))
-LibGit2.checkout!(repo, hash)
-
-# fake the supported PlotUtils version for testing (for `Pkg.develop`)
-plotutils_version = Pkg.Types.read_package(normpath(@__DIR__, "..", "Project.toml")).version
-toml = TOML.parse(read(Plots_toml, String))
-toml["compat"]["PlotUtils"] = string(plotutils_version)
-open(Plots_toml, "w") do io
-    TOML.print(io, toml)
+
+deploy_Plots() = begin
+    tmpd = mktempdir()
+    Plots_jl = joinpath(tmpd, "Plots.jl")
+    Plots_toml = joinpath(Plots_jl, "Project.toml")
+    versions = joinpath(first(DEPOT_PATH), "registries", "General", "P", "Plots", "Versions.toml")
+
+    failsafe_clone_checkout(versions, Plots_jl, "https://github.com/JuliaPlots/Plots.jl")
+    fake_supported_version!(Plots_jl)
+
+    Pkg.develop(path = Plots_jl)
+    Pkg.status(["PlotUtils", "Plots"])
+    nothing
 end
-Pkg.develop(path = Plots_jl)
-Pkg.status(["PlotUtils", "Plots"])
 
-# test basic plots creation & display
-using Plots, Test
+deploy_Makie(extended=false) = begin
+    tmpd = mktempdir()
+    Makie_jl = joinpath(tmpd, "Makie.jl")
+    versions = joinpath(first(DEPOT_PATH), "registries", "General", "M", "Makie", "Versions.toml")
+
+    failsafe_clone_checkout(versions, Makie_jl, "https://github.com/MakieOrg/Makie.jl")
+    fake_supported_version!(Makie_jl)
+
+    Pkg.develop(path = joinpath(tmpd, "Makie.jl", "MakieCore"))
+    Pkg.develop(path = joinpath(tmpd, "Makie.jl"))
+    if extended  # too costly ?
+        Pkg.develop(path = joinpath(tmpd, "Makie.jl", "ReferenceTests"))
+        Pkg.develop(path = joinpath(tmpd, "Makie.jl", "CairoMakie"))
+        # Pkg.develop(path = joinpath(tmpd, "Makie.jl", "GLMakie"))
+    end
+    Pkg.status(["PlotUtils", "MakieCore", "Makie"])
+    nothing
+end
+
+deploy_Plots()
+using Plots
+
+@testset "downstream Plots" begin
+    # test basic plots creation & display (Plots tests are too long to run)
+    true && @time for i in 1:length(Plots._examples)
+        i ∈ Plots._backend_skips[:gr] && continue  # skip unsupported examples
+        Plots._examples[i].imports ≡ nothing || continue  # skip examples requiring optional test deps
+        show(devnull, Plots.test_examples(:gr, i; disp = false))  # trigger display logic
+    end
+end
 
-@time for i in 1:length(Plots._examples)
-    i ∈ Plots._backend_skips[:gr] && continue  # skip unsupported examples
-    Plots._examples[i].imports ≡ nothing || continue  # skip examples requiring optional test deps
-    show(devnull, Plots.test_examples(:gr, i; disp = false))  # trigger display logic
+deploy_Makie()
+@testset "downstream Makie" begin
+    Pkg.test("Makie")
 end
diff --git a/test/grid.png b/test/grid.png
new file mode 100644
index 0000000..9825538
Binary files /dev/null and b/test/grid.png differ
diff --git a/test/runtests.jl b/test/runtests.jl
index ccc9a3f..63e98fd 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -108,7 +108,7 @@ end
 
 function test_ticks(x, y, ticks)
     @test issorted(ticks)
-    @test all(x .<= ticks .<= y)
+    @test all(x .≤ ticks .≤ y)
     if x < y
         @test length(ticks) >= 2
         @test is_uniformly_spaced(ticks)
@@ -132,7 +132,7 @@ end
             x, y = minmax(x, y)
             ticks, = optimize_ticks(x, y)
             @test issorted(ticks)
-            @test all(x .<= ticks .<= y)
+            @test all(x .≤ ticks .≤ y)
             # Fails:
             # @test allunique(ticks)
         end
@@ -185,7 +185,7 @@ end
         end
 
         @testset "PlotUtils.jl/issues/114" begin
-            let x = -0.1eps(), y = 0.1eps()
+            let x = -1.2eps(), y = 1.2eps()
                 test_ticks(x, y, optimize_ticks(x, y)[1])
             end
         end