diff --git a/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-no-counts.json b/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-no-counts.json
new file mode 100644
index 0000000000..713091194b
--- /dev/null
+++ b/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-no-counts.json
@@ -0,0 +1,10 @@
+{
+    "map": [
+        {
+            "usages": [
+                "U+1780",
+                "U+1781"
+            ]
+        }
+    ]
+}
\ No newline at end of file
diff --git a/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-with-counts.json b/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-with-counts.json
new file mode 100644
index 0000000000..bec0e8727b
--- /dev/null
+++ b/developer/src/kmc-analyze/test/fixtures/osk-character-use/mock-map-with-counts.json
@@ -0,0 +1,12 @@
+{
+    "map": [
+        {
+            "usages": [
+                {
+                    "char": "U+1780",
+                    "count": 2
+                }
+            ]
+        }
+    ]
+}
\ No newline at end of file
diff --git a/developer/src/kmc-analyze/test/osk-character-use-messages.tests.ts b/developer/src/kmc-analyze/test/osk-character-use-messages.tests.ts
new file mode 100644
index 0000000000..540ef3cb41
--- /dev/null
+++ b/developer/src/kmc-analyze/test/osk-character-use-messages.tests.ts
@@ -0,0 +1,60 @@
+/*
+ * Keyman is copyright (C) SIL Global. MIT License.
+ */
+import { assert } from 'chai';
+import 'mocha';
+import { TestCompilerCallbacks } from '@keymanapp/developer-test-helpers';
+import { AnalyzeOskCharacterUse } from '../src/osk-character-use/index.js';
+import { AnalyzerMessages } from '../src/analyzer-messages.js';
+import { makePathToFixture } from './helpers/index.js';
+
+describe('AnalyzeOskCharacterUse warnings', function() {
+  const callbacks = new TestCompilerCallbacks();
+
+  const MOCK_MAP_NO_COUNTS = makePathToFixture(
+    'osk-character-use',
+    'mock-map-no-counts.json'
+  );
+  const MOCK_MAP_WITH_COUNTS = makePathToFixture(
+    'osk-character-use',
+    'mock-map-with-counts.json'
+  );
+
+  this.beforeEach(function() {
+    callbacks.clear();
+  });
+
+  this.afterEach(function() {
+    if (this.currentTest?.isFailed()) {
+      callbacks.printMessages();
+    }
+  });
+
+  it('warns if previous map did not include counts but includeCounts=true', function() {
+    const a = new AnalyzeOskCharacterUse(callbacks, {
+      includeCounts: true
+    });
+
+    const result = a.unitTestEndPoints.loadPreviousMap(MOCK_MAP_NO_COUNTS);
+    assert.isNotNull(result, 'Expected map to be loaded successfully');
+    
+    assert.isTrue(
+      callbacks.hasMessage(AnalyzerMessages.WARN_PreviousMapDidNotIncludeCounts),
+      'Expected Warn_PreviousMapDidNotIncludeCounts warning'
+    );
+  });
+
+  it('warns if previous map did include counts but includeCounts=false', function() {
+    const a = new AnalyzeOskCharacterUse(callbacks, {
+      includeCounts: false
+    });
+
+    const result = a.unitTestEndPoints.loadPreviousMap(MOCK_MAP_WITH_COUNTS);
+    assert.isNotNull(result, 'Expected map to be loaded successfully');
+
+    assert.isTrue(
+      callbacks.hasMessage(AnalyzerMessages.WARN_PreviousMapDidIncludeCounts),
+      'Expected Warn_PreviousMapDidIncludeCounts warning'
+    );
+  });
+});