diff --git a/mathics/builtin/assignments/assignment.py b/mathics/builtin/assignments/assignment.py
index 0c145feca..29d7b0730 100644
--- a/mathics/builtin/assignments/assignment.py
+++ b/mathics/builtin/assignments/assignment.py
@@ -158,8 +158,6 @@ class Set(BinaryOperator, _SetOperator):
     >> B[[1;;2, 2;;-1]] = {{t, u}, {y, z}};
     >> B
      = {{1, t, u}, {4, y, z}, {7, 8, 9}}
-
-    #> x = Infinity;
     """
 
     attributes = A_HOLD_FIRST | A_PROTECTED | A_SEQUENCE_HOLD
@@ -371,12 +369,6 @@ class UpSet(BinaryOperator, _SetOperator):
      = custom
     >> UpValues[r]
      = {}
-
-    #> f[g, a + b, h] ^= 2
-     : Tag Plus in f[g, a + b, h] is Protected.
-     = 2
-    #> UpValues[h]
-     = {HoldPattern[f[g, a + b, h]] :> 2}
     """
 
     attributes = A_HOLD_FIRST | A_PROTECTED | A_SEQUENCE_HOLD
@@ -413,12 +405,6 @@ class UpSetDelayed(UpSet):
      = 2
     >> UpValues[b]
      = {HoldPattern[a[b]] :> x}
-
-    #> f[g, a + b, h] ^:= 2
-     : Tag Plus in f[g, a + b, h] is Protected.
-    #> f[a+b] ^:= 2
-     : Tag Plus in f[a + b] is Protected.
-     = $Failed
     """
 
     attributes = A_HOLD_ALL | A_PROTECTED | A_SEQUENCE_HOLD
diff --git a/mathics/builtin/assignments/clear.py b/mathics/builtin/assignments/clear.py
index f69fc034c..7ef50cb15 100644
--- a/mathics/builtin/assignments/clear.py
+++ b/mathics/builtin/assignments/clear.py
@@ -245,35 +245,6 @@ class Unset(PostfixOperator):
     >> a = b = 3;
     >> {a, {b}} =.
      = {Null, {Null}}
-
-    #> x = 2;
-    #> OwnValues[x] =.
-    #> x
-     = x
-    #> f[a][b] = 3;
-    #> SubValues[f] =.
-    #> f[a][b]
-     = f[a][b]
-    #> PrimeQ[p] ^= True
-     = True
-    #> PrimeQ[p]
-     = True
-    #> UpValues[p] =.
-    #> PrimeQ[p]
-     = False
-
-    #> a + b ^= 5;
-    #> a =.
-    #> a + b
-     = 5
-    #> {UpValues[a], UpValues[b]} =.
-     = {Null, Null}
-    #> a + b
-     = a + b
-
-    #> Unset[Messages[1]]
-     : First argument in Messages[1] is not a symbol or a string naming a symbol.
-     = $Failed
     """
 
     attributes = A_HOLD_FIRST | A_LISTABLE | A_PROTECTED | A_READ_PROTECTED
diff --git a/mathics/builtin/image/base.py b/mathics/builtin/image/base.py
index 4fbafbb5d..7cc50b52a 100644
--- a/mathics/builtin/image/base.py
+++ b/mathics/builtin/image/base.py
@@ -223,12 +223,6 @@ class ImageAtom(AtomBuiltin):
       <dd> produces the internal representation of an image from an array \
           of values for the pixels.
     </dl>
-
-    #> Image[{{{1,1,0},{0,1,1}}, {{1,0,1},{1,1,0}}}]
-     = -Image-
-
-    #> Image[{{{0,0,0,0.25},{0,0,0,0.5}}, {{0,0,0,0.5},{0,0,0,0.75}}}]
-     = -Image-
     """
 
     summary_text = "get internal representation of an image"
diff --git a/mathics/builtin/image/basic.py b/mathics/builtin/image/basic.py
index fe59024da..bf283591e 100644
--- a/mathics/builtin/image/basic.py
+++ b/mathics/builtin/image/basic.py
@@ -193,19 +193,6 @@ class ImagePartition(Builtin):
 
     >> ImagePartition[hedy, {512, 128}]
      = {{-Image-}, {-Image-}, {-Image-}, {-Image-}, {-Image-}, {-Image-}}
-
-    #> ImagePartition[hedy, 257]
-     = {{-Image-, -Image-}, {-Image-, -Image-}, {-Image-, -Image-}}
-    #> ImagePartition[hedy, 646]
-     = {{-Image-}}
-    #> ImagePartition[hedy, 647]
-     = {}
-    #> ImagePartition[hedy, {256, 300}]
-     = {{-Image-, -Image-}, {-Image-, -Image-}}
-
-    #> ImagePartition[hedy, {0, 300}]
-     : {0, 300} is not a valid size specification for image partitions.
-     = ImagePartition[-Image-, {0, 300}]
     """
 
     messages = {"arg2": "`1` is not a valid size specification for image partitions."}
diff --git a/mathics/builtin/image/composition.py b/mathics/builtin/image/composition.py
index 66cee1f47..220e8d67a 100644
--- a/mathics/builtin/image/composition.py
+++ b/mathics/builtin/image/composition.py
@@ -79,13 +79,6 @@ class ImageAdd(_ImageArithmetic):
     >> ImageAdd[i, i]
      = -Image-
 
-    #> ImageAdd[i, 0.2, i, 0.1]
-     = -Image-
-
-    #> ImageAdd[i, x]
-     : Expecting a number, image, or graphics instead of x.
-     = ImageAdd[-Image-, x]
-
     >> ein = Import["ExampleData/Einstein.jpg"];
     >> noise = RandomImage[{-0.1, 0.1}, ImageDimensions[ein]];
     >> ImageAdd[noise, ein]
@@ -117,16 +110,6 @@ class ImageMultiply(_ImageArithmetic):
     >> ImageMultiply[i, i]
      = -Image-
 
-    #> ImageMultiply[i, 0.2, i, 0.1]
-     = -Image-
-
-    #> ImageMultiply[i, x]
-     : Expecting a number, image, or graphics instead of x.
-     = ImageMultiply[-Image-, x]
-
-    S> ein = Import["ExampleData/Einstein.jpg"];
-    S> noise = RandomImage[{0.7, 1.3}, ImageDimensions[ein]];
-    S> ImageMultiply[noise, ein]
      = -Image-
     """
 
@@ -151,13 +134,6 @@ class ImageSubtract(_ImageArithmetic):
 
     >> ImageSubtract[i, i]
      = -Image-
-
-    #> ImageSubtract[i, 0.2, i, 0.1]
-     = -Image-
-
-    #> ImageSubtract[i, x]
-     : Expecting a number, image, or graphics instead of x.
-     = ImageSubtract[-Image-, x]
     """
 
     summary_text = "build an image substracting pixel values of another image "
diff --git a/mathics/builtin/image/geometric.py b/mathics/builtin/image/geometric.py
index afaa51abf..6f96b306c 100644
--- a/mathics/builtin/image/geometric.py
+++ b/mathics/builtin/image/geometric.py
@@ -156,21 +156,6 @@ class ImageReflect(Builtin):
      = -Image-
     >> ImageReflect[ein, Left -> Top]
      = -Image-
-
-    #> ein == ImageReflect[ein, Left -> Left] == ImageReflect[ein, Right -> Right] == ImageReflect[ein, Top -> Top] == ImageReflect[ein, Bottom -> Bottom]
-     = True
-    #> ImageReflect[ein, Left -> Right] == ImageReflect[ein, Right -> Left] == ImageReflect[ein, Left] == ImageReflect[ein, Right]
-     = True
-    #> ImageReflect[ein, Bottom -> Top] == ImageReflect[ein, Top -> Bottom] == ImageReflect[ein, Top] == ImageReflect[ein, Bottom]
-     = True
-    #> ImageReflect[ein, Left -> Top] == ImageReflect[ein, Right -> Bottom]     (* Transpose *)
-     = True
-    #> ImageReflect[ein, Left -> Bottom] == ImageReflect[ein, Right -> Top]     (* Anti-Transpose *)
-     = True
-
-    #> ImageReflect[ein, x -> Top]
-     : x -> Top is not a valid 2D reflection specification.
-     = ImageReflect[-Image-, x -> Top]
     """
 
     summary_text = "reflect an image"
@@ -239,10 +224,6 @@ class ImageRotate(Builtin):
 
     >> ImageRotate[ein, Pi / 4]
      = -Image-
-
-    #> ImageRotate[ein, ein]
-     : Angle -Image- should be a real number, one of Top, Bottom, Left, Right, or a rule from one to another.
-     = ImageRotate[-Image-, -Image-]
     """
 
     messages = {
diff --git a/mathics/builtin/image/misc.py b/mathics/builtin/image/misc.py
index 89256f919..8437ab920 100644
--- a/mathics/builtin/image/misc.py
+++ b/mathics/builtin/image/misc.py
@@ -119,18 +119,6 @@ class RandomImage(Builtin):
 
     >> RandomImage[1, {100, 100}]
      = -Image-
-
-    #> RandomImage[0.5]
-     = -Image-
-    #> RandomImage[{0.1, 0.9}]
-     = -Image-
-    #> RandomImage[0.9, {400, 600}]
-     = -Image-
-    #> RandomImage[{0.1, 0.5}, {400, 600}]
-     = -Image-
-
-    #> RandomImage[{0.1, 0.5}, {400, 600}, ColorSpace -> "RGB"]
-     = -Image-
     """
 
     options = {"ColorSpace": "Automatic"}
diff --git a/mathics/builtin/image/pixel.py b/mathics/builtin/image/pixel.py
index ebd519daa..e4b114b4c 100644
--- a/mathics/builtin/image/pixel.py
+++ b/mathics/builtin/image/pixel.py
@@ -26,21 +26,6 @@ class PixelValue(Builtin):
     >> hedy = Import["ExampleData/hedy.tif"];
     >> PixelValue[hedy, {1, 1}]
      = {0.439216, 0.356863, 0.337255}
-    #> {82 / 255, 22 / 255, 57 / 255} // N  (* pixel byte values from bottom left corner *)
-     = {0.321569, 0.0862745, 0.223529}
-
-    #> PixelValue[hedy, {0, 1}];
-     : Padding not implemented for PixelValue.
-    #> PixelValue[hedy, {512, 1}]
-     = {0.0509804, 0.0509804, 0.0588235}
-    #> PixelValue[hedy, {647, 1}];
-     : Padding not implemented for PixelValue.
-    #> PixelValue[hedy, {1, 0}];
-     : Padding not implemented for PixelValue.
-    #> PixelValue[hedy, {1, 512}]
-     = {0.286275, 0.4, 0.423529}
-    #> PixelValue[hedy, {1, 801}];
-     : Padding not implemented for PixelValue.
     """
 
     messages = {"nopad": "Padding not implemented for PixelValue."}
diff --git a/mathics/builtin/image/properties.py b/mathics/builtin/image/properties.py
index 38ffc4dbb..50313a205 100644
--- a/mathics/builtin/image/properties.py
+++ b/mathics/builtin/image/properties.py
@@ -93,10 +93,6 @@ class ImageData(Builtin):
 
     >> ImageData[Image[{{0, 1}, {1, 0}, {1, 1}}], "Bit"]
      = {{0, 1}, {1, 0}, {1, 1}}
-
-    #> ImageData[img, "Bytf"]
-     : Unsupported pixel format "Bytf".
-     = ImageData[-Image-, Bytf]
     """
 
     messages = {"pixelfmt": 'Unsupported pixel format "``".'}
diff --git a/test/builtin/image/test_image.py b/test/builtin/image/test_image.py
new file mode 100644
index 000000000..fb79fe470
--- /dev/null
+++ b/test/builtin/image/test_image.py
@@ -0,0 +1,198 @@
+# -*- coding: utf-8 -*-
+"""
+Unit tests for mathics.builtins.image.colors
+
+Largely tests error messages when parameters are incorrect.
+"""
+from test.helper import check_evaluation, session
+
+import pytest
+
+
+@pytest.mark.parametrize(
+    ("str_expr", "str_expected", "msgs", "assert_failure_msg"),
+    [
+        (None, None, None, None),
+        #
+        # Base Image Atom
+        #
+        (
+            "Image[{{{1,1,0},{0,1,1}}, {{1,0,1},{1,1,0}}}]",
+            "-Image-",
+            None,
+            "Image Atom B&W",
+        ),
+        (
+            "Image[{{{0,0,0,0.25},{0,0,0,0.5}}, {{0,0,0,0.5},{0,0,0,0.75}}}]",
+            "-Image-",
+            None,
+            "Image Atom RGB",
+        ),
+        #
+        # Operations over images
+        #
+        ('hedy = Import["ExampleData/hedy.tif"];', "Null", None, "Load an image"),
+        (
+            'ImageData[hedy, "Bytf"]',
+            "ImageData[-Image-, Bytf]",
+            ('Unsupported pixel format "Bytf".',),
+            "Wrong Image Data",
+        ),
+        (
+            "ImagePartition[hedy, 257]",
+            "{{-Image-, -Image-}, {-Image-, -Image-}, {-Image-, -Image-}}",
+            None,
+            None,
+        ),
+        ("ImagePartition[hedy, 646]", "{{-Image-}}", None, None),
+        ("ImagePartition[hedy, 647]", "{}", None, None),
+        (
+            "ImagePartition[hedy, {256, 300}]",
+            "{{-Image-, -Image-}, {-Image-, -Image-}}",
+            None,
+            None,
+        ),
+        (
+            "ImagePartition[hedy, {0, 300}]",
+            "ImagePartition[-Image-, {0, 300}]",
+            ("{0, 300} is not a valid size specification for image partitions.",),
+            None,
+        ),
+        (
+            "{82 / 255, 22 / 255, 57 / 255} // N",
+            "{0.321569, 0.0862745, 0.223529}",
+            None,
+            "pixel byte values from bottom left corner",
+        ),
+        (
+            "PixelValue[hedy, {0, 1}];",
+            "Null",
+            ("Padding not implemented for PixelValue.",),
+            None,
+        ),
+        ("PixelValue[hedy, {512, 1}]", "{0.0509804, 0.0509804, 0.0588235}", None, None),
+        (
+            "PixelValue[hedy, {647, 1}];",
+            "Null",
+            ("Padding not implemented for PixelValue.",),
+            None,
+        ),
+        (
+            "PixelValue[hedy, {1, 0}];",
+            "Null",
+            ("Padding not implemented for PixelValue.",),
+            None,
+        ),
+        ("PixelValue[hedy, {1, 512}]", "{0.286275, 0.4, 0.423529}", None, None),
+        (
+            "PixelValue[hedy, {1, 801}];",
+            "Null",
+            ("Padding not implemented for PixelValue.",),
+            None,
+        ),
+        #
+        # Composition
+        #
+        (
+            "i = Image[{{0, 0.5, 0.2, 0.1, 0.9}, {1.0, 0.1, 0.3, 0.8, 0.6}}];",
+            "Null",
+            None,
+            None,
+        ),
+        ("ImageAdd[i, 0.2, i, 0.1]", "-Image-", None, None),
+        (
+            "ImageAdd[i, x]",
+            "ImageAdd[-Image-, x]",
+            ("Expecting a number, image, or graphics instead of x.",),
+            None,
+        ),
+        ("ImageMultiply[i, 0.2, i, 0.1]", "-Image-", None, None),
+        (
+            "ImageMultiply[i, x]",
+            "ImageMultiply[-Image-, x]",
+            ("Expecting a number, image, or graphics instead of x.",),
+            None,
+        ),
+        (
+            'ein = Import["ExampleData/Einstein.jpg"]; noise = RandomImage[{0.7, 1.3}, ImageDimensions[ein]];ImageMultiply[noise, ein]',
+            "-Image-",
+            None,
+            "Multiply Image by random noise",
+        ),
+        ("ImageSubtract[i, 0.2, i, 0.1]", "-Image-", None, None),
+        (
+            "ImageSubtract[i, x]",
+            "ImageSubtract[-Image-, x]",
+            ("Expecting a number, image, or graphics instead of x.",),
+            None,
+        ),
+        #
+        # Random
+        #
+        ("RandomImage[0.5]", "-Image-", None, None),
+        ("RandomImage[{0.1, 0.9}]", "-Image-", None, None),
+        ("RandomImage[0.9, {400, 600}]", "-Image-", None, None),
+        ("RandomImage[{0.1, 0.5}, {400, 600}]", "-Image-", None, None),
+        (
+            'RandomImage[{0.1, 0.5}, {400, 600}, ColorSpace -> "RGB"]',
+            "-Image-",
+            None,
+            None,
+        ),
+        #
+        # Geometry
+        #
+        (
+            "ein == ImageReflect[ein, Left -> Left] == ImageReflect[ein, Right -> Right] == ImageReflect[ein, Top -> Top] == ImageReflect[ein, Bottom -> Bottom]",
+            "True",
+            None,
+            None,
+        ),
+        (
+            "ImageReflect[ein, Left -> Right] == ImageReflect[ein, Right -> Left] == ImageReflect[ein, Left] == ImageReflect[ein, Right]",
+            "True",
+            None,
+            None,
+        ),
+        (
+            "ImageReflect[ein, Bottom -> Top] == ImageReflect[ein, Top -> Bottom] == ImageReflect[ein, Top] == ImageReflect[ein, Bottom]",
+            "True",
+            None,
+            None,
+        ),
+        (
+            "ImageReflect[ein, Left -> Top] == ImageReflect[ein, Right -> Bottom]",
+            "True",
+            None,
+            "Transpose",
+        ),
+        (
+            "ImageReflect[ein, Left -> Bottom] == ImageReflect[ein, Right -> Top]",
+            "True",
+            None,
+            "Anti-Transpose",
+        ),
+        (
+            "ImageReflect[ein, x -> Top]",
+            "ImageReflect[-Image-, x -> Top]",
+            ("x -> Top is not a valid 2D reflection specification.",),
+            None,
+        ),
+        (
+            "ImageRotate[ein, ein]",
+            "ImageRotate[-Image-, -Image-]",
+            (
+                "Angle -Image- should be a real number, one of Top, Bottom, Left, Right, or a rule from one to another.",
+            ),
+            None,
+        ),
+    ],
+)
+def test_private_doctest(str_expr, str_expected, msgs, assert_failure_msg):
+    check_evaluation(
+        str_expr,
+        str_expected,
+        hold_expected=True,
+        expected_messages=msgs,
+        failure_message=assert_failure_msg,
+    )
diff --git a/test/builtin/test_assignment.py b/test/builtin/test_assignment.py
index e9c846aac..476180249 100644
--- a/test/builtin/test_assignment.py
+++ b/test/builtin/test_assignment.py
@@ -413,3 +413,40 @@ def test_process_assign_other():
                 "Cannot set $ModuleNumber to -1; value must be a positive integer."
             ],
         )
+
+
+@pytest.mark.parametrize(
+    ("str_expr", "str_expected", "msgs", "failure_msg"),
+    [
+        (None, None, None, None),
+        # From Clear
+        ("x = 2;OwnValues[x]=.;x", "x", None, "Erase Ownvalues"),
+        ("f[a][b] = 3; SubValues[f] =.;f[a][b]", "f[a][b]", None, "Erase Subvalues"),
+        ("PrimeQ[p] ^= True; PrimeQ[p]", "True", None, "Subvalues"),
+        ("UpValues[p]=.; PrimeQ[p]", "False", None, "Erase Subvalues"),
+        ("a + b ^= 5; a =.; a + b", "5", None, None),
+        ("{UpValues[a], UpValues[b]} =.; a+b", "a+b", None, None),
+        (
+            "Unset[Messages[1]]",
+            "$Failed",
+            [
+                "First argument in Messages[1] is not a symbol or a string naming a symbol."
+            ],
+            "Unset Message",
+        ),
+        # From assignent
+        (
+            "f[g, a + b, h] ^= 2",
+            "2",
+            ("Tag Plus in f[g, a + b, h] is Protected.",),
+            "Upset to protected symbols fails",
+        ),
+        ("UpValues[h]", "{HoldPattern[f[g, a + b, h]] :> 2}", None, None),
+        (" g[a+b] ^:= 2", "$Failed", ("Tag Plus in g[a + b] is Protected.",), None),
+        (" g[a+b]", "g[a + b]", None, None),
+    ],
+)
+def test_private_doctests(str_expr, str_expected, msgs, failure_msg):
+    check_evaluation(
+        str_expr, str_expected, expected_messages=msgs, failure_message=failure_msg
+    )