diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_colors_from_palette.js b/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_colors_from_palette.js
deleted file mode 100644
index e397bda763f1..000000000000
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_colors_from_palette.js
+++ /dev/null
@@ -1,42 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { getColorsFromPalette } from '../../lib/get_colors_from_palette';
-import {
-  grayscalePalette,
-  gradientPalette,
-} from '../../../canvas_plugin_src/functions/common/__tests__/fixtures/test_styles';
-
-describe('getColorsFromPalette', () => {
-  it('returns the array of colors from a palette object when gradient is false', () => {
-    expect(getColorsFromPalette(grayscalePalette, 20)).to.eql(grayscalePalette.colors);
-  });
-
-  it('returns an array of colors with equidistant colors with length equal to the number of series when gradient is true', () => {
-    const result = getColorsFromPalette(gradientPalette, 16);
-    expect(result)
-      .to.have.length(16)
-      .and.to.eql([
-        '#ffffff',
-        '#eeeeee',
-        '#dddddd',
-        '#cccccc',
-        '#bbbbbb',
-        '#aaaaaa',
-        '#999999',
-        '#888888',
-        '#777777',
-        '#666666',
-        '#555555',
-        '#444444',
-        '#333333',
-        '#222222',
-        '#111111',
-        '#000000',
-      ]);
-  });
-});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_legend_config.js b/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_legend_config.js
deleted file mode 100644
index ba43db7a8367..000000000000
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_legend_config.js
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License;
- * you may not use this file except in compliance with the Elastic License.
- */
-
-import expect from '@kbn/expect';
-import { getLegendConfig } from '../get_legend_config';
-
-describe('getLegendConfig', () => {
-  describe('show', () => {
-    it('hides the legend', () => {
-      expect(getLegendConfig(false, 2))
-        .to.only.have.key('show')
-        .and.to.have.property('show', false);
-      expect(getLegendConfig(false, 10))
-        .to.only.have.key('show')
-        .and.to.have.property('show', false);
-    });
-
-    it('hides the legend when there are less than 2 series', () => {
-      expect(getLegendConfig(false, 1))
-        .to.only.have.key('show')
-        .and.to.have.property('show', false);
-      expect(getLegendConfig(true, 1))
-        .to.only.have.key('show')
-        .and.to.have.property('show', false);
-    });
-
-    it('shows the legend when there are two or more series', () => {
-      expect(getLegendConfig('sw', 2)).to.have.property('show', true);
-      expect(getLegendConfig(true, 5)).to.have.property('show', true);
-    });
-  });
-
-  describe('position', () => {
-    it('sets the position of the legend', () => {
-      expect(getLegendConfig('nw')).to.have.property('position', 'nw');
-      expect(getLegendConfig('ne')).to.have.property('position', 'ne');
-      expect(getLegendConfig('sw')).to.have.property('position', 'sw');
-      expect(getLegendConfig('se')).to.have.property('position', 'se');
-    });
-
-    it("defaults to 'ne'", () => {
-      expect(getLegendConfig(true)).to.have.property('position', 'ne');
-      expect(getLegendConfig('foo')).to.have.property('position', 'ne');
-    });
-  });
-});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/autocomplete.test.ts b/x-pack/legacy/plugins/canvas/common/lib/autocomplete.test.ts
index 616e45c86c4a..88bb32c846c2 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/autocomplete.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/autocomplete.test.ts
@@ -7,184 +7,195 @@
 jest.mock('ui/new_platform');
 import { functionSpecs } from '../../__tests__/fixtures/function_specs';
 
-import { getAutocompleteSuggestions } from './autocomplete';
+import { getAutocompleteSuggestions, getFnArgDefAtPosition } from './autocomplete';
 
-describe('getAutocompleteSuggestions', () => {
-  it('should suggest functions', () => {
-    const suggestions = getAutocompleteSuggestions(functionSpecs, '', 0);
-    expect(suggestions.length).toBe(functionSpecs.length);
-    expect(suggestions[0].start).toBe(0);
-    expect(suggestions[0].end).toBe(0);
+describe('autocomplete', () => {
+  describe('getFnArgDefAtPosition', () => {
+    it('should return function definition for plot', () => {
+      const expression = 'plot ';
+      const def = getFnArgDefAtPosition(functionSpecs, expression, expression.length);
+      const plotFn = functionSpecs.find(spec => spec.name === 'plot');
+      expect(def.fnDef).toBe(plotFn);
+    });
   });
 
-  it('should suggest functions filtered by text', () => {
-    const expression = 'pl';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, 0);
-    const nonmatching = suggestions.map(s => s.text).filter(text => !text.includes(expression));
-    expect(nonmatching.length).toBe(0);
-    expect(suggestions[0].start).toBe(0);
-    expect(suggestions[0].end).toBe(expression.length);
-  });
+  describe('getAutocompleteSuggestions', () => {
+    it('should suggest functions', () => {
+      const suggestions = getAutocompleteSuggestions(functionSpecs, '', 0);
+      expect(suggestions.length).toBe(functionSpecs.length);
+      expect(suggestions[0].start).toBe(0);
+      expect(suggestions[0].end).toBe(0);
+    });
 
-  it('should suggest arguments', () => {
-    const expression = 'plot ';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const plotFn = functionSpecs.find(spec => spec.name === 'plot');
-    expect(suggestions.length).toBe(Object.keys(plotFn.args).length);
-    expect(suggestions[0].start).toBe(expression.length);
-    expect(suggestions[0].end).toBe(expression.length);
-  });
+    it('should suggest functions filtered by text', () => {
+      const expression = 'pl';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, 0);
+      const nonmatching = suggestions.map(s => s.text).filter(text => !text.includes(expression));
+      expect(nonmatching.length).toBe(0);
+      expect(suggestions[0].start).toBe(0);
+      expect(suggestions[0].end).toBe(expression.length);
+    });
 
-  it('should suggest arguments filtered by text', () => {
-    const expression = 'plot axis';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const plotFn = functionSpecs.find(spec => spec.name === 'plot');
-    const matchingArgs = Object.keys(plotFn.args).filter(key => key.includes('axis'));
-    expect(suggestions.length).toBe(matchingArgs.length);
-    expect(suggestions[0].start).toBe('plot '.length);
-    expect(suggestions[0].end).toBe('plot axis'.length);
-  });
+    it('should suggest arguments', () => {
+      const expression = 'plot ';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const plotFn = functionSpecs.find(spec => spec.name === 'plot');
+      expect(suggestions.length).toBe(Object.keys(plotFn.args).length);
+      expect(suggestions[0].start).toBe(expression.length);
+      expect(suggestions[0].end).toBe(expression.length);
+    });
 
-  it('should suggest values', () => {
-    const expression = 'shape shape=';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
-    expect(suggestions.length).toBe(shapeFn.args.shape.options.length);
-    expect(suggestions[0].start).toBe(expression.length);
-    expect(suggestions[0].end).toBe(expression.length);
-  });
+    it('should suggest arguments filtered by text', () => {
+      const expression = 'plot axis';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const plotFn = functionSpecs.find(spec => spec.name === 'plot');
+      const matchingArgs = Object.keys(plotFn.args).filter(key => key.includes('axis'));
+      expect(suggestions.length).toBe(matchingArgs.length);
+      expect(suggestions[0].start).toBe('plot '.length);
+      expect(suggestions[0].end).toBe('plot axis'.length);
+    });
 
-  it('should suggest values filtered by text', () => {
-    const expression = 'shape shape=ar';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
-    const matchingValues = shapeFn.args.shape.options.filter((key: string) => key.includes('ar'));
-    expect(suggestions.length).toBe(matchingValues.length);
-    expect(suggestions[0].start).toBe(expression.length - 'ar'.length);
-    expect(suggestions[0].end).toBe(expression.length);
-  });
+    it('should suggest values', () => {
+      const expression = 'shape shape=';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
+      expect(suggestions.length).toBe(shapeFn.args.shape.options.length);
+      expect(suggestions[0].start).toBe(expression.length);
+      expect(suggestions[0].end).toBe(expression.length);
+    });
 
-  it('should suggest functions inside an expression', () => {
-    const expression = 'if {}';
-    const suggestions = getAutocompleteSuggestions(
-      functionSpecs,
-      expression,
-      expression.length - 1
-    );
-    expect(suggestions.length).toBe(functionSpecs.length);
-    expect(suggestions[0].start).toBe(expression.length - 1);
-    expect(suggestions[0].end).toBe(expression.length - 1);
-  });
+    it('should suggest values filtered by text', () => {
+      const expression = 'shape shape=ar';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
+      const matchingValues = shapeFn.args.shape.options.filter((key: string) => key.includes('ar'));
+      expect(suggestions.length).toBe(matchingValues.length);
+      expect(suggestions[0].start).toBe(expression.length - 'ar'.length);
+      expect(suggestions[0].end).toBe(expression.length);
+    });
 
-  it('should suggest arguments inside an expression', () => {
-    const expression = 'if {lt }';
-    const suggestions = getAutocompleteSuggestions(
-      functionSpecs,
-      expression,
-      expression.length - 1
-    );
-    const ltFn = functionSpecs.find(spec => spec.name === 'lt');
-    expect(suggestions.length).toBe(Object.keys(ltFn.args).length);
-    expect(suggestions[0].start).toBe(expression.length - 1);
-    expect(suggestions[0].end).toBe(expression.length - 1);
-  });
+    it('should suggest functions inside an expression', () => {
+      const expression = 'if {}';
+      const suggestions = getAutocompleteSuggestions(
+        functionSpecs,
+        expression,
+        expression.length - 1
+      );
+      expect(suggestions.length).toBe(functionSpecs.length);
+      expect(suggestions[0].start).toBe(expression.length - 1);
+      expect(suggestions[0].end).toBe(expression.length - 1);
+    });
 
-  it('should suggest values inside an expression', () => {
-    const expression = 'if {shape shape=}';
-    const suggestions = getAutocompleteSuggestions(
-      functionSpecs,
-      expression,
-      expression.length - 1
-    );
-    const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
-    expect(suggestions.length).toBe(shapeFn.args.shape.options.length);
-    expect(suggestions[0].start).toBe(expression.length - 1);
-    expect(suggestions[0].end).toBe(expression.length - 1);
-  });
+    it('should suggest arguments inside an expression', () => {
+      const expression = 'if {lt }';
+      const suggestions = getAutocompleteSuggestions(
+        functionSpecs,
+        expression,
+        expression.length - 1
+      );
+      const ltFn = functionSpecs.find(spec => spec.name === 'lt');
+      expect(suggestions.length).toBe(Object.keys(ltFn.args).length);
+      expect(suggestions[0].start).toBe(expression.length - 1);
+      expect(suggestions[0].end).toBe(expression.length - 1);
+    });
 
-  it('should suggest values inside quotes', () => {
-    const expression = 'shape shape="ar"';
-    const suggestions = getAutocompleteSuggestions(
-      functionSpecs,
-      expression,
-      expression.length - 1
-    );
-    const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
-    const matchingValues = shapeFn.args.shape.options.filter((key: string) => key.includes('ar'));
-    expect(suggestions.length).toBe(matchingValues.length);
-    expect(suggestions[0].start).toBe(expression.length - '"ar"'.length);
-    expect(suggestions[0].end).toBe(expression.length);
-  });
+    it('should suggest values inside an expression', () => {
+      const expression = 'if {shape shape=}';
+      const suggestions = getAutocompleteSuggestions(
+        functionSpecs,
+        expression,
+        expression.length - 1
+      );
+      const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
+      expect(suggestions.length).toBe(shapeFn.args.shape.options.length);
+      expect(suggestions[0].start).toBe(expression.length - 1);
+      expect(suggestions[0].end).toBe(expression.length - 1);
+    });
 
-  it('should prioritize functions that start with text', () => {
-    const expression = 't';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const tableIndex = suggestions.findIndex(suggestion => suggestion.text.includes('table'));
-    const alterColumnIndex = suggestions.findIndex(suggestion =>
-      suggestion.text.includes('alterColumn')
-    );
-    expect(tableIndex).toBeLessThan(alterColumnIndex);
-  });
+    it('should suggest values inside quotes', () => {
+      const expression = 'shape shape="ar"';
+      const suggestions = getAutocompleteSuggestions(
+        functionSpecs,
+        expression,
+        expression.length - 1
+      );
+      const shapeFn = functionSpecs.find(spec => spec.name === 'shape');
+      const matchingValues = shapeFn.args.shape.options.filter((key: string) => key.includes('ar'));
+      expect(suggestions.length).toBe(matchingValues.length);
+      expect(suggestions[0].start).toBe(expression.length - '"ar"'.length);
+      expect(suggestions[0].end).toBe(expression.length);
+    });
 
-  it('should prioritize functions that match the previous function type', () => {
-    const expression = 'plot | ';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const renderIndex = suggestions.findIndex(suggestion => suggestion.text.includes('render'));
-    const anyIndex = suggestions.findIndex(suggestion => suggestion.text.includes('any'));
-    expect(renderIndex).toBeLessThan(anyIndex);
-  });
+    it('should prioritize functions that start with text', () => {
+      const expression = 't';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const tableIndex = suggestions.findIndex(suggestion => suggestion.text.includes('table'));
+      const alterColumnIndex = suggestions.findIndex(suggestion =>
+        suggestion.text.includes('alterColumn')
+      );
+      expect(tableIndex).toBeLessThan(alterColumnIndex);
+    });
 
-  it('should alphabetize functions', () => {
-    const expression = '';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const metricIndex = suggestions.findIndex(suggestion => suggestion.text.includes('metric'));
-    const anyIndex = suggestions.findIndex(suggestion => suggestion.text.includes('any'));
-    expect(anyIndex).toBeLessThan(metricIndex);
-  });
+    it('should prioritize functions that match the previous function type', () => {
+      const expression = 'plot | ';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const renderIndex = suggestions.findIndex(suggestion => suggestion.text.includes('render'));
+      const anyIndex = suggestions.findIndex(suggestion => suggestion.text.includes('any'));
+      expect(renderIndex).toBeLessThan(anyIndex);
+    });
 
-  it('should prioritize arguments that start with text', () => {
-    const expression = 'plot y';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const yaxisIndex = suggestions.findIndex(suggestion => suggestion.text.includes('yaxis'));
-    const defaultStyleIndex = suggestions.findIndex(suggestion =>
-      suggestion.text.includes('defaultStyle')
-    );
-    expect(yaxisIndex).toBeLessThan(defaultStyleIndex);
-  });
+    it('should alphabetize functions', () => {
+      const expression = '';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const metricIndex = suggestions.findIndex(suggestion => suggestion.text.includes('metric'));
+      const anyIndex = suggestions.findIndex(suggestion => suggestion.text.includes('any'));
+      expect(anyIndex).toBeLessThan(metricIndex);
+    });
 
-  it('should prioritize unnamed arguments', () => {
-    const expression = 'case ';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const whenIndex = suggestions.findIndex(suggestion => suggestion.text.includes('when'));
-    const thenIndex = suggestions.findIndex(suggestion => suggestion.text.includes('then'));
-    expect(whenIndex).toBeLessThan(thenIndex);
-  });
+    it('should prioritize arguments that start with text', () => {
+      const expression = 'plot y';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const yaxisIndex = suggestions.findIndex(suggestion => suggestion.text.includes('yaxis'));
+      const defaultStyleIndex = suggestions.findIndex(suggestion =>
+        suggestion.text.includes('defaultStyle')
+      );
+      expect(yaxisIndex).toBeLessThan(defaultStyleIndex);
+    });
 
-  it('should alphabetize arguments', () => {
-    const expression = 'plot ';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    const yaxisIndex = suggestions.findIndex(suggestion => suggestion.text.includes('yaxis'));
-    const defaultStyleIndex = suggestions.findIndex(suggestion =>
-      suggestion.text.includes('defaultStyle')
-    );
-    expect(defaultStyleIndex).toBeLessThan(yaxisIndex);
-  });
+    it('should prioritize unnamed arguments', () => {
+      const expression = 'case ';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const whenIndex = suggestions.findIndex(suggestion => suggestion.text.includes('when'));
+      const thenIndex = suggestions.findIndex(suggestion => suggestion.text.includes('then'));
+      expect(whenIndex).toBeLessThan(thenIndex);
+    });
 
-  it('should quote string values', () => {
-    const expression = 'shape shape=';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    expect(suggestions[0].text.trim()).toMatch(/^".*"$/);
-  });
+    it('should alphabetize arguments', () => {
+      const expression = 'plot ';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      const yaxisIndex = suggestions.findIndex(suggestion => suggestion.text.includes('yaxis'));
+      const defaultStyleIndex = suggestions.findIndex(suggestion =>
+        suggestion.text.includes('defaultStyle')
+      );
+      expect(defaultStyleIndex).toBeLessThan(yaxisIndex);
+    });
 
-  it('should not quote sub expression value suggestions', () => {
-    const expression = 'plot font=';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    expect(suggestions[0].text.trim()).toBe('{font}');
-  });
+    it('should quote string values', () => {
+      const expression = 'shape shape=';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      expect(suggestions[0].text.trim()).toMatch(/^".*"$/);
+    });
 
-  it('should not quote booleans', () => {
-    const expression = 'table paginate=true';
-    const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
-    expect(suggestions[0].text.trim()).toBe('true');
+    it('should not quote sub expression value suggestions', () => {
+      const expression = 'plot font=';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      expect(suggestions[0].text.trim()).toBe('{font}');
+    });
+
+    it('should not quote booleans', () => {
+      const expression = 'table paginate=true';
+      const suggestions = getAutocompleteSuggestions(functionSpecs, expression, expression.length);
+      expect(suggestions[0].text.trim()).toBe('true');
+    });
   });
 });
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/dataurl.test.ts b/x-pack/legacy/plugins/canvas/common/lib/dataurl.test.ts
similarity index 77%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/dataurl.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/dataurl.test.ts
index acd9e6d1821d..8bfe723bc2ae 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/dataurl.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/dataurl.test.ts
@@ -4,13 +4,15 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { isValidDataUrl, parseDataUrl } from '../dataurl';
+import { isValidDataUrl, parseDataUrl } from './dataurl';
 
 const BASE64_TEXT = 'data:text/plain;charset=utf-8;base64,VGhpcyBpcyBhIHRlc3Q=';
 const BASE64_SVG =
   'data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciLz4=';
 const BASE64_PIXEL =
   'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk8PxfDwADYgHJvQ16TAAAAABJRU5ErkJggg==';
+const INVALID_BASE64_PIXEL =
+  'data:image/png;%89PNG%0D%0A%1A%0A%00%00%00%0DIHDR%00%00%00%01%00%00%00%01%08%06%00%00%00%1F%15%C4%89%0';
 
 const RAW_TEXT = 'data:text/plain;charset=utf-8,This%20is%20a%20test';
 const RAW_SVG =
@@ -20,10 +22,13 @@ const RAW_PIXEL =
 
 describe('dataurl', () => {
   describe('isValidDataUrl', () => {
-    test('invalid data url', () => {
+    it('returns false for an invalid data url', () => {
       expect(isValidDataUrl('somestring')).toBe(false);
     });
-    test('valid data urls', () => {
+    it('returns false for an empty string', () => {
+      expect(isValidDataUrl('')).toBe(false);
+    });
+    it('returns true for valid data urls', () => {
       expect(isValidDataUrl(BASE64_TEXT)).toBe(true);
       expect(isValidDataUrl(BASE64_SVG)).toBe(true);
       expect(isValidDataUrl(BASE64_PIXEL)).toBe(true);
@@ -34,10 +39,13 @@ describe('dataurl', () => {
   });
 
   describe('dataurl.parseDataUrl', () => {
-    test('invalid data url', () => {
+    it('returns null for an invalid data url', () => {
       expect(parseDataUrl('somestring')).toBeNull();
     });
-    test('text data urls', () => {
+    it('returns null for an invalid base64 image', () => {
+      expect(parseDataUrl(INVALID_BASE64_PIXEL)).toBeNull();
+    });
+    it('returns correct values for text data urls', () => {
       expect(parseDataUrl(BASE64_TEXT)).toEqual({
         charset: 'utf-8',
         data: null,
@@ -55,7 +63,7 @@ describe('dataurl', () => {
         mimetype: 'text/plain',
       });
     });
-    test('png data urls', () => {
+    it('returns correct values for png data urls', () => {
       expect(parseDataUrl(RAW_PIXEL)).toBeNull();
       expect(parseDataUrl(BASE64_PIXEL)).toEqual({
         charset: undefined,
@@ -66,7 +74,7 @@ describe('dataurl', () => {
         mimetype: 'image/png',
       });
     });
-    test('svg data urls', () => {
+    it('returns correct values for svg data urls', () => {
       expect(parseDataUrl(RAW_SVG)).toEqual({
         charset: undefined,
         data: null,
diff --git a/x-pack/legacy/plugins/canvas/common/lib/errors.test.js b/x-pack/legacy/plugins/canvas/common/lib/errors.test.js
new file mode 100644
index 000000000000..a589fde5dadb
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/errors.test.js
@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { RenderError } from './errors';
+
+describe('errors', () => {
+  it('creates a test error', () => {
+    // eslint-disable-next-line new-cap
+    const throwTestError = () => RenderError();
+    expect(throwTestError.name).toBe('throwTestError');
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/expression_form_handlers.test.js b/x-pack/legacy/plugins/canvas/common/lib/expression_form_handlers.test.js
new file mode 100644
index 000000000000..ae46661b50cd
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/expression_form_handlers.test.js
@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { ExpressionFormHandlers } from './expression_form_handlers';
+
+describe('ExpressionFormHandlers', () => {
+  it('executes destroy function', () => {
+    const handler = new ExpressionFormHandlers();
+    handler.onDestroy(() => {
+      return 'DESTROYED!';
+    });
+    expect(handler.destroy()).toBe('DESTROYED!');
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/fetch.test.ts b/x-pack/legacy/plugins/canvas/common/lib/fetch.test.ts
new file mode 100644
index 000000000000..d06c2af4f062
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/fetch.test.ts
@@ -0,0 +1,24 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { fetch, arrayBufferFetch } from './fetch';
+
+describe('fetch', () => {
+  it('test fetch headers', () => {
+    expect(fetch.defaults.headers.Accept).toBe('application/json');
+    expect(fetch.defaults.headers['Content-Type']).toBe('application/json');
+    expect(fetch.defaults.headers['kbn-xsrf']).toBe('professionally-crafted-string-of-text');
+  });
+
+  it('test arrayBufferFetch headers', () => {
+    expect(arrayBufferFetch.defaults.headers.Accept).toBe('application/json');
+    expect(arrayBufferFetch.defaults.headers['Content-Type']).toBe('application/json');
+    expect(arrayBufferFetch.defaults.headers['kbn-xsrf']).toBe(
+      'professionally-crafted-string-of-text'
+    );
+    expect(arrayBufferFetch.defaults.responseType).toBe('arraybuffer');
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/get_colors_from_palette.test.js b/x-pack/legacy/plugins/canvas/common/lib/get_colors_from_palette.test.js
new file mode 100644
index 000000000000..ebc72db1f67f
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/get_colors_from_palette.test.js
@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import {
+  grayscalePalette,
+  gradientPalette,
+} from '../../canvas_plugin_src/functions/common/__tests__/fixtures/test_styles';
+import { getColorsFromPalette } from './get_colors_from_palette';
+
+describe('getColorsFromPalette', () => {
+  it('returns the array of colors from a palette object when gradient is false', () => {
+    expect(getColorsFromPalette(grayscalePalette, 20)).toBe(grayscalePalette.colors);
+  });
+
+  it('returns an array of colors with equidistant colors with length equal to the number of series when gradient is true', () => {
+    const result = getColorsFromPalette(gradientPalette, 16);
+    expect(result).toEqual([
+      '#ffffff',
+      '#eeeeee',
+      '#dddddd',
+      '#cccccc',
+      '#bbbbbb',
+      '#aaaaaa',
+      '#999999',
+      '#888888',
+      '#777777',
+      '#666666',
+      '#555555',
+      '#444444',
+      '#333333',
+      '#222222',
+      '#111111',
+      '#000000',
+    ]);
+    expect(result).toHaveLength(16);
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_field_type.test.ts b/x-pack/legacy/plugins/canvas/common/lib/get_field_type.test.ts
similarity index 87%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/get_field_type.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/get_field_type.test.ts
index 34cfbb5a2bef..82e724c33ecc 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/get_field_type.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/get_field_type.test.ts
@@ -4,11 +4,11 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { getFieldType } from '../get_field_type';
 import {
   emptyTable,
   testTable,
-} from '../../../canvas_plugin_src/functions/common/__tests__/fixtures/test_tables';
+} from '../../canvas_plugin_src/functions/common/__tests__/fixtures/test_tables';
+import { getFieldType } from './get_field_type';
 
 describe('getFieldType', () => {
   it('returns type of a field in a datatable', () => {
diff --git a/x-pack/legacy/plugins/canvas/common/lib/get_legend_config.test.js b/x-pack/legacy/plugins/canvas/common/lib/get_legend_config.test.js
new file mode 100644
index 000000000000..b9ab9ae6aba5
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/get_legend_config.test.js
@@ -0,0 +1,40 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { getLegendConfig } from './get_legend_config';
+
+describe('getLegendConfig', () => {
+  describe('show', () => {
+    it('hides the legend', () => {
+      expect(getLegendConfig(false, 2)).toHaveProperty('show', false);
+      expect(getLegendConfig(false, 10)).toHaveProperty('show', false);
+    });
+
+    it('hides the legend when there are less than 2 series', () => {
+      expect(getLegendConfig(false, 1)).toHaveProperty('show', false);
+      expect(getLegendConfig(true, 1)).toHaveProperty('show', false);
+    });
+
+    it('shows the legend when there are two or more series', () => {
+      expect(getLegendConfig('sw', 2)).toHaveProperty('show', true);
+      expect(getLegendConfig(true, 5)).toHaveProperty('show', true);
+    });
+  });
+
+  describe('position', () => {
+    it('sets the position of the legend', () => {
+      expect(getLegendConfig('nw')).toHaveProperty('position', 'nw');
+      expect(getLegendConfig('ne')).toHaveProperty('position', 'ne');
+      expect(getLegendConfig('sw')).toHaveProperty('position', 'sw');
+      expect(getLegendConfig('se')).toHaveProperty('position', 'se');
+    });
+
+    it("defaults to 'ne'", () => {
+      expect(getLegendConfig(true)).toHaveProperty('position', 'ne');
+      expect(getLegendConfig('foo')).toHaveProperty('position', 'ne');
+    });
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/handlebars.test.js b/x-pack/legacy/plugins/canvas/common/lib/handlebars.test.js
new file mode 100644
index 000000000000..5fcb2d42395f
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/handlebars.test.js
@@ -0,0 +1,19 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { testTable } from '../../canvas_plugin_src/functions/common/__tests__/fixtures/test_tables';
+import { Handlebars } from './handlebars';
+
+describe('handlebars', () => {
+  it('registers math function and returns argument error', () => {
+    const template = Handlebars.compile("test math: {{math rows 'mean(price * quantity)' 2}}");
+    expect(template()).toBe('test math: MATH ERROR: first argument must be an array');
+  });
+  it('evaluates math function successfully', () => {
+    const template = Handlebars.compile("test math: {{math rows 'mean(price * quantity)' 2}}");
+    expect(template(testTable)).toBe('test math: 82164.33');
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/hex_to_rgb.test.ts b/x-pack/legacy/plugins/canvas/common/lib/hex_to_rgb.test.ts
similarity index 80%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/hex_to_rgb.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/hex_to_rgb.test.ts
index d9aa56314948..00b4b40fa983 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/hex_to_rgb.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/hex_to_rgb.test.ts
@@ -4,21 +4,21 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { hexToRgb } from '../hex_to_rgb';
+import { hexToRgb } from './hex_to_rgb';
 
 describe('hexToRgb', () => {
-  test('invalid hex', () => {
+  it('returns null for an invalid hex', () => {
     expect(hexToRgb('hexadecimal')).toBeNull();
     expect(hexToRgb('#00')).toBeNull();
     expect(hexToRgb('#00000')).toBeNull();
   });
-  test('shorthand', () => {
+  it('returns correct value for shorthand hex codes', () => {
     expect(hexToRgb('#000')).toEqual([0, 0, 0]);
     expect(hexToRgb('#FFF')).toEqual([255, 255, 255]);
     expect(hexToRgb('#fff')).toEqual([255, 255, 255]);
     expect(hexToRgb('#fFf')).toEqual([255, 255, 255]);
   });
-  test('longhand', () => {
+  it('returns correct value for longhand hex codes', () => {
     expect(hexToRgb('#000000')).toEqual([0, 0, 0]);
     expect(hexToRgb('#ffffff')).toEqual([255, 255, 255]);
     expect(hexToRgb('#fffFFF')).toEqual([255, 255, 255]);
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/httpurl.test.ts b/x-pack/legacy/plugins/canvas/common/lib/httpurl.test.ts
similarity index 97%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/httpurl.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/httpurl.test.ts
index 2a7cef7cf423..65bc2469647a 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/httpurl.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/httpurl.test.ts
@@ -4,7 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { isValidHttpUrl } from '../httpurl';
+import { isValidHttpUrl } from './httpurl';
 
 describe('httpurl.isValidHttpUrl', () => {
   it('matches HTTP URLs', () => {
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/pivot_object_array.test.ts b/x-pack/legacy/plugins/canvas/common/lib/pivot_object_array.test.ts
similarity index 97%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/pivot_object_array.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/pivot_object_array.test.ts
index 6f6d42e7129a..faf319769cab 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/pivot_object_array.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/pivot_object_array.test.ts
@@ -4,7 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { pivotObjectArray } from '../pivot_object_array';
+import { pivotObjectArray } from './pivot_object_array';
 
 interface Car {
   make: string;
diff --git a/x-pack/legacy/plugins/canvas/common/lib/resolve_dataurl.test.js b/x-pack/legacy/plugins/canvas/common/lib/resolve_dataurl.test.js
new file mode 100644
index 000000000000..bbbd4f51d483
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/resolve_dataurl.test.js
@@ -0,0 +1,41 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { missingImage } from '../../common/lib/missing_asset';
+import { resolveFromArgs, resolveWithMissingImage } from './resolve_dataurl';
+
+describe('resolve_dataurl', () => {
+  describe('resolveFromArgs', () => {
+    it('finds and returns the dataurl from args successfully', () => {
+      const args = {
+        name: 'dataurl',
+        argType: 'imageUpload',
+        dataurl: [missingImage, 'test2'],
+      };
+      expect(resolveFromArgs(args)).toBe(missingImage);
+    });
+    it('finds and returns null for invalid dataurl', () => {
+      const args = {
+        name: 'dataurl',
+        argType: 'imageUpload',
+        dataurl: ['invalid url', 'test2'],
+      };
+      expect(resolveFromArgs(args)).toBe(null);
+    });
+  });
+
+  describe('resolveWithMissingImage', () => {
+    it('returns valid dataurl', () => {
+      expect(resolveWithMissingImage(missingImage)).toBe(missingImage);
+    });
+    it('returns missingImage for invalid dataurl', () => {
+      expect(resolveWithMissingImage('invalid dataurl')).toBe(missingImage);
+    });
+    it('returns null for null dataurl', () => {
+      expect(resolveWithMissingImage(null)).toBe(null);
+    });
+  });
+});
diff --git a/x-pack/legacy/plugins/canvas/common/lib/__tests__/unquote_string.test.ts b/x-pack/legacy/plugins/canvas/common/lib/unquote_string.test.ts
similarity index 94%
rename from x-pack/legacy/plugins/canvas/common/lib/__tests__/unquote_string.test.ts
rename to x-pack/legacy/plugins/canvas/common/lib/unquote_string.test.ts
index e67e46f9e5da..d6eeb9392f40 100644
--- a/x-pack/legacy/plugins/canvas/common/lib/__tests__/unquote_string.test.ts
+++ b/x-pack/legacy/plugins/canvas/common/lib/unquote_string.test.ts
@@ -4,7 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
-import { unquoteString } from '../unquote_string';
+import { unquoteString } from './unquote_string';
 
 describe('unquoteString', () => {
   it('removes double quotes', () => {
diff --git a/x-pack/legacy/plugins/canvas/common/lib/url.test.js b/x-pack/legacy/plugins/canvas/common/lib/url.test.js
new file mode 100644
index 000000000000..d49d12c6bf38
--- /dev/null
+++ b/x-pack/legacy/plugins/canvas/common/lib/url.test.js
@@ -0,0 +1,21 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { missingImage } from '../../common/lib/missing_asset';
+import { isValidUrl } from './url';
+
+describe('resolve_dataurl', () => {
+  it('returns valid dataurl', () => {
+    expect(isValidUrl(missingImage)).toBe(true);
+  });
+  it('returns valid http url', () => {
+    const httpurl = 'https://test.com/s/';
+    expect(isValidUrl(httpurl)).toBe(true);
+  });
+  it('returns false for invalid url', () => {
+    expect(isValidUrl('test')).toBe(false);
+  });
+});