tests: add better tests

Author: naveen521kk

manim/mobject/svg/text_mobject.py

@@ -20,7 +20,6 @@
 from ...mobject.types.vectorized_mobject import VGroup
 from ...utils.config_ops import digest_config
 
-
 TEXT_MOB_SCALE_FACTOR = 0.05
 
 
@@ -391,7 +390,6 @@ def text2svg1(self):
         surface.finish()
         return file_name
 
-
 class Paragraph(VGroup):
     r"""Display a paragraph of text.
 
@@ -684,7 +682,7 @@ def __init__(self, text: str, **config):
         if self.height is None and self.width is None:
             self.scale(TEXT_MOB_SCALE_FACTOR)
 
-    def remove_last_M(self, file_name: str):
+    def remove_last_M(self, file_name: str): # pylint: disable=invalid-name
         """Internally used. Use to format the rendered SVG files."""
         with open(file_name, "r") as fpr:
             content = fpr.read()
@@ -719,13 +717,13 @@ def full2short(self, config):
         for kwargs in [config, self.CONFIG]:
             if "text2color" in kwargs:
                 kwargs["t2c"] = kwargs.pop("text2color")
-            if kwargs.__contains__("text2font"):
+            if "text2font" in kwargs:
                 kwargs["t2f"] = kwargs.pop("text2font")
-            if kwargs.__contains__("text2gradient"):
+            if "text2gradient" in kwargs:
                 kwargs["t2g"] = kwargs.pop("text2gradient")
-            if kwargs.__contains__("text2slant"):
+            if "text2slant" in kwargs:
                 kwargs["t2s"] = kwargs.pop("text2slant")
-            if kwargs.__contains__("text2weight"):
+            if "text2weight" in kwargs:
                 kwargs["t2w"] = kwargs.pop("text2weight")
 
     def set_color_by_t2c(self, t2c=None):
@@ -736,7 +734,8 @@ def set_color_by_t2c(self, t2c=None):
                 self.chars[start:end].set_color(color)
 
     def set_color_by_t2g(self, t2g=None):
-        """Internally used. Sets gradient colors for specified strings. Behaves similarly to ``set_color_by_t2c``."""
+        """Internally used. Sets gradient colors for specified
+        strings. Behaves similarly to ``set_color_by_t2c``."""
         t2g = t2g if t2g else self.t2g
         for word, gradient in list(t2g.items()):
             for start, end in self.find_indexes(word, self.original_text):
@@ -842,10 +841,11 @@ def text2svg(self):
         """Internally used function.
         Convert the text to SVG using Pango
         """
-        # anti-aliasing
         size = self.size * 10
         line_spacing = self.line_spacing * 10
         dir_name = file_writer_config["text_dir"]
+        if not os.path.exists(dir_name):
+            os.makedirs(dir_name)
         hash_name = self.text2hash()
         file_name = os.path.join(dir_name, hash_name) + ".svg"
         if os.path.exists(file_name):

tests/test_pango.py

@@ -1,124 +1,139 @@
-from manim import PangoText, START_X, START_Y, SVGMobject
+"""Tests :class:`PangoText` by comparing SVG files created.
+"""
 import os
+import re
+
 import cairocffi
 import pangocairocffi
 import pangocffi
+from manim import START_X, START_Y, PangoText, SVGMobject
 
-rtl_text = """صباح الخير
+RTL_TEXT: str = """صباح الخير
 مرحبا جميعا"""
 
-width = 600
-height = 400
+WIDTH: int = 600
+HEIGTH: int = 400
+folder: str = os.path.abspath(os.path.join("media", "texts"))
+filename: str = os.path.join(folder, "hello.svg")
+
+
+def remove_last_M(file_path: str) -> None:  # pylint: disable=invalid-name
+    """Format SVG file so that it can be compared"""
+    with open(file_path, "r") as fpr:
+        content = fpr.read()
+    content = re.sub(r'Z M [^A-Za-z]*? "\/>', 'Z "/>', content)
+    with open(file_path, "w") as fpw:
+        fpw.write(content)
+
+
+def compare_SVGObject_with_PangoText(  # pylint: disable=invalid-name
+    text: PangoText, svg_path: str
+) -> bool:
+    """Checks for the path_string formed by PangoText and Formed SVG file.
+    Uses SVGMobject as it parses the SVG and returns the path_string
+    """
+    remove_last_M(svg_path)  # to prevent issue displaying
+    svg = SVGMobject(svg_path)
+    assert len(text.submobjects) == len(svg.submobjects)
+    assert (text.points == svg.points).all()
+    for i in range(len(text.submobjects)):
+        assert text.submobjects[i].path_string == svg.submobjects[i].path_string
+        assert (
+            text.submobjects[i].sheen_direction == svg.submobjects[i].sheen_direction
+        ).all()
+        assert (
+            text.submobjects[i].stroke_rgbas == svg.submobjects[i].stroke_rgbas
+        ).all()
+    return True
 
 
-def test_general_text_svgobject():
-    """Checks number of submobjects generated when directly called using ``SVGMobject``"""
+def test_general_text_svgobject() -> None:
+    """Checks number of submobjects generated when directly
+    called using ``SVGMobject``
+    """
     text = "hello"
     size = 1
-    folder = os.path.abspath(os.path.join("media", "texts"))
-    if not os.path.exists(folder):
-        os.makedirs(folder)
-    filename = os.path.join(folder, "hello.svg")
-    a = PangoText(text, size=10)
-    pangoManim = os.path.join(folder, a.text2hash() + ".svg")
-    surface = cairocffi.SVGSurface(filename, width, height)
+    temp_pango_text = PangoText(text, size=size)
+    surface = cairocffi.SVGSurface(filename, WIDTH, HEIGTH)
     context = cairocffi.Context(surface)
     context.move_to(START_X, START_Y)
     layout = pangocairocffi.create_layout(context)
-    layout.set_width(pangocffi.units_from_double(width))
+    layout.set_width(pangocffi.units_from_double(WIDTH))
     fontdesc = pangocffi.FontDescription()
     fontdesc.set_size(pangocffi.units_from_double(size * 10))
     layout.set_font_description(fontdesc)
     layout.set_text(text)
     pangocairocffi.show_layout(context, layout)
     surface.finish()
-    b = SVGMobject(filename)
-    assert len(a.submobjects) == len(b.submobjects)
+    assert compare_SVGObject_with_PangoText(temp_pango_text, filename)
 
 
-def test_rtl_text_text_svgobject():
-    """Checks number of submobjects generated when directly called using ``SVGMobject``"""
+def test_rtl_text_to_svgobject() -> None:
+    """Checks number of submobjects generated when directly
+    called using ``SVGMobject``"""
     size = 1
-    text = rtl_text
-    folder = os.path.abspath(os.path.join("media", "texts"))
-    if not os.path.exists(folder):
-        os.makedirs(folder)
-    filename = os.path.join(folder, "hello.svg")
-    a = PangoText(text, size=1)
-    pangoManim = os.path.join(folder, a.text2hash() + ".svg")
-    surface = cairocffi.SVGSurface(filename, width, height)
+    text = RTL_TEXT.replace("\n", "")
+    temp_pango_text = PangoText(text, size=1)
+    surface = cairocffi.SVGSurface(filename, WIDTH, HEIGTH)
     context = cairocffi.Context(surface)
     context.move_to(START_X, START_Y)
     layout = pangocairocffi.create_layout(context)
-    layout.set_width(pangocffi.units_from_double(width))
+    layout.set_width(pangocffi.units_from_double(WIDTH))
     fontdesc = pangocffi.FontDescription()
     fontdesc.set_size(pangocffi.units_from_double(size * 10))
     layout.set_font_description(fontdesc)
     layout.set_text(text)
     pangocairocffi.show_layout(context, layout)
     surface.finish()
-    b = SVGMobject(filename)
-    assert len(a.submobjects) == len(b.submobjects)
+    assert compare_SVGObject_with_PangoText(temp_pango_text, filename)
 
 
-def test_font_face():
+def test_font_face() -> None:
     """Checks font face using submobject len"""
     size = 1
-    text = rtl_text
+    text = RTL_TEXT.replace("\n", "")
     font_face = "sans"
-    folder = os.path.abspath(os.path.join("media", "texts"))
-    if not os.path.exists(folder):
-        os.makedirs(folder)
-    filename = os.path.join(folder, "hello.svg")
-    a = PangoText(text, size=1, font=font_face)
-    pangoManim = os.path.join(folder, a.text2hash() + ".svg")
-    surface = cairocffi.SVGSurface(filename, width, height)
+    temp_pango_text = PangoText(text, size=1, font=font_face)
+    surface = cairocffi.SVGSurface(filename, WIDTH, HEIGTH)
     context = cairocffi.Context(surface)
     context.move_to(START_X, START_Y)
     layout = pangocairocffi.create_layout(context)
-    layout.set_width(pangocffi.units_from_double(width))
+    layout.set_width(pangocffi.units_from_double(WIDTH))
     fontdesc = pangocffi.FontDescription()
     fontdesc.set_family(font_face)
     fontdesc.set_size(pangocffi.units_from_double(size * 10))
     layout.set_font_description(fontdesc)
     layout.set_text(text)
     pangocairocffi.show_layout(context, layout)
     surface.finish()
-    b = SVGMobject(filename)
-    assert len(a.submobjects) == len(b.submobjects)
+    assert compare_SVGObject_with_PangoText(temp_pango_text, filename)
 
 
-def test_whether_svg_file_created():
+def test_whether_svg_file_created() -> None:
     """Checks Whether SVG file is created in desired location"""
-    a = PangoText("hello", size=1)
-    folder = os.path.abspath(os.path.join("media", "texts"))
-    if not os.path.exists(folder):
-        os.makedirs(folder)
-    theoPath = os.path.abspath(os.path.join(folder, a.text2hash() + ".svg"))
-    actualPath = os.path.abspath(a.text2svg())
-    assert theoPath == actualPath
+    temp_pango_text = PangoText("hello", size=1)
+    theo_path = os.path.abspath(
+        os.path.join(folder, temp_pango_text.text2hash() + ".svg")
+    )
+    actual_path = os.path.abspath(temp_pango_text.text2svg())
+    assert theo_path == actual_path
 
 
-def test_tabs_replace():
-    """Checks whether are there in end svg image. Pango should handle tabs and line breaks."""
+def test_tabs_replace() -> None:
+    """Checks whether are there in end svg image.
+    Pango should handle tabs and line breaks."""
     size = 1
-    folder = os.path.abspath(os.path.join("media", "texts"))
-    if not os.path.exists(folder):
-        os.makedirs(folder)
-    a = PangoText("hello\thi\nf")
-    assert a.text == "hellohif"
-    pangoManim = os.path.join(folder, a.text2hash() + ".svg")
-    filename = os.path.join(folder, "hello.svg")
-    surface = cairocffi.SVGSurface(filename, width, height)
+    temp_pango_text = PangoText("hello\thi\nf")
+    assert temp_pango_text.text == "hellohif"
+    surface = cairocffi.SVGSurface(filename, WIDTH, HEIGTH)
     context = cairocffi.Context(surface)
     context.move_to(START_X, START_Y)
     layout = pangocairocffi.create_layout(context)
-    layout.set_width(pangocffi.units_from_double(width))
+    layout.set_width(pangocffi.units_from_double(WIDTH))
     fontdesc = pangocffi.FontDescription()
     fontdesc.set_size(pangocffi.units_from_double(size * 10))
     layout.set_font_description(fontdesc)
-    layout.set_text("hello\thi\nf")
+    layout.set_text("hellohif")
     pangocairocffi.show_layout(context, layout)
     surface.finish()
-    b = SVGMobject(filename)
-    assert len(a.submobjects) == len(b.submobjects)
+    assert compare_SVGObject_with_PangoText(temp_pango_text, filename)