diff --git a/docs/changelog.txt b/docs/changelog.txt
index 5433e719e..fc1bf6e36 100644
--- a/docs/changelog.txt
+++ b/docs/changelog.txt
@@ -43,6 +43,7 @@ changelog.txt uses a syntax similar to RST, with a few special sequences:
 - `embark-assistant`: fixed an issue causing incursion resource matching (e.g. sand/clay) to skip some tiles if those resources were provided only through incursions
 - `embark-assistant`: corrected river size determination by performing it at the MLT level rather than the world tile one
 - `search`: fixed an issue where search options might not display if screens were destroyed and recreated programmatically (e.g. with `quickfort`)
+- `workflow`: fixed an error when creating constraints on "mill plants" jobs and some other plant-related jobs
 - `zone`: fixed an issue causing the ``enumnick`` subcommand to run when attempting to run ``assign``, ``unassign``, or ``slaughter``
 
 ## Misc Improvements
diff --git a/plugins/lua/workflow.lua b/plugins/lua/workflow.lua
index 9122f290d..bdcd02bcb 100644
--- a/plugins/lua/workflow.lua
+++ b/plugins/lua/workflow.lua
@@ -196,27 +196,24 @@ function job_outputs.MakeCrafts(callback, job)
 end
 
 local plant_products = {
-    BrewDrink = 'DRINK',
     MillPlants = 'MILL',
     ProcessPlants = 'THREAD',
-    ProcessPlantsBag = 'LEAVES',
     ProcessPlantsBarrel = 'EXTRACT_BARREL',
     ProcessPlantsVial = 'EXTRACT_VIAL',
     ExtractFromPlants = 'EXTRACT_STILL_VIAL',
 }
 
 for job,flag in pairs(plant_products) do
-    local ttag = 'type_'..string.lower(flag)
-    local itag = 'idx_'..string.lower(flag)
+    local tag = string.lower(flag)
     job_outputs[job] = function(callback, job)
         local mat_type, mat_index = -1, -1
         local seed_type, seed_index = -1, -1
         local mat = dfhack.matinfo.decode(job.job_items[0])
         if mat and mat.plant and mat.plant.flags[flag] then
-            mat_type = mat.plant.material_defs[ttag]
-            mat_index = mat.plant.material_defs[itag]
-            seed_type = mat.plant.material_defs['type_seed']
-            seed_index = mat.plant.material_defs['idx_seed']
+            mat_type = mat.plant.material_defs.type[tag]
+            mat_index = mat.plant.material_defs.idx[tag]
+            seed_type = mat.plant.material_defs.type.seed
+            seed_index = mat.plant.material_defs.idx.seed
         end
         local mat_mask = { }
         if flag ~= 'LEAVES' then
@@ -358,4 +355,10 @@ function listWeakenedConstraints(outputs)
     return variants
 end
 
+if dfhack.internal.IN_TEST then
+    test_data = {
+        job_outputs = job_outputs,
+    }
+end
+
 return _ENV
diff --git a/test/main.lua b/test/main.lua
index 83a35d165..be3993fb4 100644
--- a/test/main.lua
+++ b/test/main.lua
@@ -104,6 +104,16 @@ function delay(frames)
     script.sleep(frames, 'frames')
 end
 
+function clean_require(module)
+    -- wrapper around require() - forces a clean load of every module to ensure
+    -- that modules checking for dfhack.internal.IN_TEST at load time behave
+    -- properly
+    if package.loaded[module] then
+        reload(module)
+    end
+    return require(module)
+end
+
 function ensure_title_screen()
     if df.viewscreen_titlest:is_instance(dfhack.gui.getCurViewscreen()) then
         return
@@ -153,6 +163,7 @@ function build_test_env()
         },
         expect = {},
         delay = delay,
+        require = clean_require,
     }
     local private = {
         checks = 0,
@@ -206,6 +217,7 @@ function save_test_status(status)
 end
 
 function finish_tests()
+    dfhack.internal.IN_TEST = false
     if done_command then
         dfhack.run_command(done_command)
     end
@@ -220,7 +232,9 @@ function load_tests(file, tests)
         dfhack.printerr('Failed to load file: ' .. tostring(err))
         return false
     else
+        dfhack.internal.IN_TEST = true
         local ok, err = pcall(code)
+        dfhack.internal.IN_TEST = false
         if not ok then
             dfhack.printerr('Error when running file: ' .. tostring(err))
             return false
@@ -260,7 +274,9 @@ function run_test(test, status, counts)
     test.private.checks = 0
     test.private.checks_ok = 0
     counts.tests = counts.tests + 1
+    dfhack.internal.IN_TEST = true
     local ok, err = pcall(test.func)
+    dfhack.internal.IN_TEST = false
     local passed = false
     if not ok then
         dfhack.printerr('test errored: ' .. test.name .. ': ' .. tostring(err))
diff --git a/test/plugins/workflow.lua b/test/plugins/workflow.lua
new file mode 100644
index 000000000..af8d32793
--- /dev/null
+++ b/test/plugins/workflow.lua
@@ -0,0 +1,7 @@
+local workflow = require('plugins.workflow')
+
+function test.job_outputs()
+    for job_type in pairs(workflow.test_data.job_outputs) do
+        expect.true_(df.job_type[job_type], "Found unrecognized job type: " .. tostring(job_type))
+    end
+end
diff --git a/test/test.lua b/test/test.lua
new file mode 100644
index 000000000..11f038d66
--- /dev/null
+++ b/test/test.lua
@@ -0,0 +1,3 @@
+function test.internal_in_test()
+    expect.true_(dfhack.internal.IN_TEST)
+end