Make gxpdf more testable and setup PDF diff tests

.github/workflows/ci.yml

@@ -41,6 +41,25 @@ jobs:
     - name: Lint
       run: |
         flake8 -v
+    - name: Install apt deps with cache
+      uses: awalsh128/cache-apt-pkgs-action@latest
+      if: "matrix.python-version == '3.11'"
+      with:
+        packages: diff-pdf
+        version: 1.0
+    - uses: actions/cache@v3
+      name: Tectonic Cache
+      if: "matrix.python-version == '3.11'"
+      with:
+        path: ~/.cache/Tectonic
+        key: ${{ runner.os }}-tectonic-${{ hashFiles('**/*.tex') }}
+        restore-keys: |
+          ${{ runner.os }}-tectonic-
+    - uses: wtfjoke/setup-tectonic@v2
+      if: "matrix.python-version == '3.11'"
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        biber-version: "latest"
     - name: Test
       run: |
         PYTEST_ARGS=();

.gitignore

@@ -139,3 +139,6 @@ examples/**/*.tex
 
 # Mac
 .DS_Store
+
+test/generated
+test/diff

galgebra/gprinter.py

@@ -26,7 +26,7 @@ class LaTeX:
 
     latex_preamble = """
 \\pagestyle{empty}
-\\usepackage[latin1]{inputenc}
+\\usepackage[utf8]{inputenc}
 \\usepackage{amsmath}
 \\usepackage{amsfonts}
 \\usepackage{amssymb}
@@ -196,7 +196,7 @@ def gprint(*xargs):
     return
 
 
-def gxpdf(filename=None, paper=(14, 11), crop=False, png=False, prog=False, debug=False, pt='10pt', pdfprog='pdflatex'):
+def gxpdf(filename=None, paper=(14, 11), crop=False, png=False, prog=False, debug=False, pt='10pt', pdfprog='pdflatex', evince=True, rm=True, null=True):
 
     """
     Post processes LaTeX output (see comments below), adds preamble and
@@ -208,10 +208,11 @@ def gxpdf(filename=None, paper=(14, 11), crop=False, png=False, prog=False, debu
     crop        True        Use "pdfcrop" to crop output file (pdfcrop must be installed, linux only)
     png         True        Use "convert" to produce png output (imagemagick must be installed, linux only)
 
-    We assume that if xpdf() is called then Format() has been called at the beginning of the program.
+    We assume that if gxpdf() is called then gFormat() has been called at the beginning of the program.
     """
 
     latex_str = paper_format(paper, pt)+LaTeX.latex_preamble+LaTeX.latex_str+r'\end{document}'
+
 
     if filename is None:
         pyfilename = sys.argv[0]
@@ -221,13 +222,13 @@ def gxpdf(filename=None, paper=(14, 11), crop=False, png=False, prog=False, debu
     else:
         tex_filename = filename
         pdf_filename = tex_filename.replace('.tex', '.pdf')
+        rootfilename = tex_filename.replace('.tex', '')
 
     if debug:
         print('latex file =', filename)
 
-    latex_file = open(tex_filename, 'w')
-    latex_file.write(latex_str)
-    latex_file.close()
+    with open(tex_filename, 'w') as latex_file:
+        latex_file.write(latex_str)
 
     if pdfprog is not None:
         sys_cmd = SYS_CMD[sys.platform]
@@ -237,17 +238,22 @@ def gxpdf(filename=None, paper=(14, 11), crop=False, png=False, prog=False, debu
             print('pdflatex path =', pdflatex)
             # os.system(pdfprog + ' ' + filename[:-4])
         else:  # Works for Linux don't know about Windows
-            subprocess.call([pdfprog, tex_filename, sys_cmd['null']])
+            if null:
+                subprocess.call([pdfprog, tex_filename, sys_cmd['null']])
+            else:
+                subprocess.call([pdfprog, tex_filename])
             # os.system(pdfprog + ' ' + filename[:-4] + sys_cmd['null'])
 
-        subprocess.call([sys_cmd['evince'], pdf_filename])
+        if evince:
+            subprocess.call([sys_cmd['evince'], pdf_filename])
 
         # eval(input('!!!!Return to continue!!!!\n'))
 
-        if debug:
-            subprocess.call([sys_cmd['rm'], rootfilename+'.aux ', rootfilename+'.log'])
-        else:
-            subprocess.call([sys_cmd['rm'], rootfilename+'.aux ', rootfilename+'.log ', rootfilename+'.tex'])
+        if rm:
+            if debug:
+                subprocess.call([sys_cmd['rm'], rootfilename+'.aux ', rootfilename+'.log'])
+            else:
+                subprocess.call([sys_cmd['rm'], rootfilename+'.aux ', rootfilename+'.log ', rootfilename+'.tex'])
         if crop:
             subprocess.call(['pdfcrop', pdf_filename])
             subprocess.call(['rm', pdf_filename])

test/test_gprinter.py

@@ -0,0 +1,73 @@
+from __future__ import annotations
+
+import os
+import unittest
+import pytest
+import subprocess
+from pathlib import Path
+
+# Make SymPy available to this program:
+import sympy 
+from sympy import symbols
+
+# Make GAlgebra available to this program:
+from galgebra.ga import Ga  
+# from galgebra.mv import *
+from galgebra.printer import Fmt, GaPrinter, Format
+# Fmt:       sets the way that a multivector's basis expansion is output.
+# GaPrinter: makes GA output a little more readable.
+# Format:    turns on latex printer.
+from galgebra.gprinter import gFormat, gprint, gxpdf
+
+ROOT = Path(__file__).parent.parent
+DIR_TEST = ROOT / 'test'
+DIR_GENERATED = DIR_TEST / 'generated'
+DIR_FIXTURES = DIR_TEST / 'fixtures'
+DIR_DIFF = DIR_TEST / 'diff'
+
+
+class TestGprinter(unittest.TestCase):
+    # @pytest.mark.skipif("TEST_GXPDF" not in os.environ, reason="Only run if TEST_GXPDF is set")
+    def test_gxpdf(self):
+        gFormat()
+        # Set up standard G^3 geometric algebra
+        g3coords = (x, y, z) = symbols('x y z', real=True)  # Without real=True, symbols are complex
+        g3 = Ga(r'\mathbf{e}', g=[1, 1, 1], coords=g3coords)
+        (ex, ey, ez) = g3.mv()      # Program names of basis vectors.
+        (exr, eyr, ezr) = g3.mvr()  # Program names of reciprocal basis vectors.
+
+        B = g3.mv('B', 'bivector')
+        Fmt(1)  # Set Fmt globally
+        gprint(r'\mathbf{B} =', B)         # B will be bold.
+        gprint(r'\mathbf{B} =', B.Fmt(3))  # Fmt(3) here only.
+        gprint(r'\mathbf{B} =', B)         # Global Fmt remembered.
+
+        gprint(r'\mathbf{B}^2 =', B*B)
+
+        M = g3.mv('M', 'mv')
+        gprint(r'\langle \mathbf{M} \rangle_2 =', M.grade(2)) 
+        # grade(2) could be replaced by, e.g., odd(), or omitted altogether.
+
+        gprint(r'\alpha_1\mathbf{X}/\gamma_r^3')
+
+        grad = g3.grad
+
+        gprint(r'{\nabla} = ', grad)
+
+        # mkdir -p
+        os.makedirs(DIR_GENERATED, exist_ok=True)
+        os.makedirs(DIR_DIFF, exist_ok=True)
+        os.chdir(DIR_GENERATED)
+
+        gxpdf('test_gprinter.tex', pdfprog='tectonic', rm=False, null=False, evince=False)
+
+        os.chdir(ROOT)
+        retcode = subprocess.call([
+            'diff-pdf',
+            '--output-diff=%s' % (DIR_DIFF / 'test_gprinter-diff.pdf'),
+            DIR_FIXTURES / 'test_gprinter.pdf',
+            DIR_GENERATED / 'test_gprinter.pdf'
+        ])
+        assert retcode == 0
+
+        # os.system('pdf2svg test_gprinter.pdf test_gprinter.svg')