From 8fbcc3a5fb4e9071719bbc2296abec5e8c20080f Mon Sep 17 00:00:00 2001
From: icweaver <weaveric@gmail.com>
Date: Tue, 1 Apr 2025 21:56:09 -0700
Subject: [PATCH] err msgs + tests

---
 src/ccd2rgb.jl   |  6 +++++-
 test/runtests.jl | 13 +++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/ccd2rgb.jl b/src/ccd2rgb.jl
index 773ea3a5..135d485e 100644
--- a/src/ccd2rgb.jl
+++ b/src/ccd2rgb.jl
@@ -56,9 +56,12 @@ function composecolors(
     if length(images) == 3 && isnothing(cmap)
         cmap = ["red", "green", "blue"]
     end
-    if length(cmap) < length(images)
+    if _cmap_len(cmap) < length(images)
         error("Please provide a color channel for each image")
     end
+    if _cmap_len(cmap) > length(images)
+        error("Please provide an image for each color channel")
+    end
 
     # Use imview to render each channel to RGBA
     images_rendered = broadcast(images, cmap, clims, stretch, contrast, bias) do image, cmap, clims, stretch, contrast, bias
@@ -77,4 +80,5 @@ function composecolors(
     end
     return combined
 end
+_cmap_len(cmap) = isnothing(cmap) ? 0 : length(cmap)
 export composechannels
diff --git a/test/runtests.jl b/test/runtests.jl
index 8d4a40ef..1c8a2ea2 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -378,3 +378,16 @@ end
 
 # include("plots.jl")
 # include("ccd2rgb.jl")
+# TODO: Put this into ccd2rgb.jl later?
+@testset "ccd2rgb" begin
+    img1, img2, img3 = eachslice(rand(3, 4, 3); dims=3)
+    img4 = rand(3, 5)
+    @test_throws ErrorException("At least one image is required.") composecolors([], ["red", "blue", "green"])
+    @test_throws ErrorException("Images must have the same dimensions to compose them.") composecolors([img1, img2, img4], ["red", "blue", "green"])
+    @test_throws ErrorException("Please provide a color channel for each image") composecolors([img1, img2, img3], ["red", "blue"])
+    @test_throws ErrorException("Please provide a color channel for each image") composecolors([img1, img2], ["red"])
+    @test_throws ErrorException("Please provide a color channel for each image") composecolors([img1, img2])
+    @test_throws ErrorException("Please provide an image for each color channel") composecolors([img1, img2, img3], ["red", "blue", "green", "maroon"])
+    @test_throws ErrorException("Please provide an image for each color channel") composecolors([img1, img2], ["red", "blue", "green"])
+    @test_throws ErrorException("Please provide an image for each color channel") composecolors([img1], ["red", "blue"])
+end