diff --git a/crates/export/src/pptx.rs b/crates/export/src/pptx.rs
index 2edc0e25c..49765000d 100644
--- a/crates/export/src/pptx.rs
+++ b/crates/export/src/pptx.rs
@@ -358,398 +358,4 @@ xmlns:a=\"http://schemas.openxmlformats.org/drawingml/2006/main\" type=\"blank\"
 }
 
 #[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::Block;
-    use crate::tests::part;
-
-    fn sample_page() -> Page {
-        Page {
-            width: 720.0,
-            height: 540.0,
-            blocks: vec![
-                Block {
-                    text: "Q3 Business Update".into(),
-                    rect: [72.0, 460.0, 500.0, 500.0],
-                    size: 28.0,
-                    bold: true,
-                    italic: false,
-                    color: [0.1, 0.2, 0.3],
-                    rotation: 0.0,
-                    space_around: [false; 2],
-                },
-                Block {
-                    text: "Revenue grew 25% year over year across all regions.".into(),
-                    rect: [72.0, 380.0, 500.0, 410.0],
-                    size: 14.0,
-                    bold: false,
-                    italic: false,
-                    color: [0.0; 3],
-                    rotation: 0.0,
-                    space_around: [false; 2],
-                },
-                Block {
-                    text: "Operational expenses remained flat.".into(),
-                    rect: [72.0, 340.0, 500.0, 370.0],
-                    size: 14.0,
-                    bold: false,
-                    italic: true,
-                    color: [0.0; 3],
-                    rotation: 0.0,
-                    space_around: [false; 2],
-                },
-            ],
-            images: vec![Image {
-                ext: "png",
-                bytes: b"\x89PNG\r\n\x1a\n\0\0\0\rIHDR\0\0\0\x02\0\0\0\x03".as_slice().into(),
-                rect: [72.0, 150.0, 300.0, 300.0],
-                size: [228.0, 150.0],
-                rotation: 0.0,
-            }],
-            background: None,
-        }
-    }
-
-    #[test]
-    pub fn pptx_is_a_presentationml_package() {
-        let p = sample_page();
-        let bytes = pptx(&[p], "Executive Deck");
-        assert!(bytes.starts_with(b"PK"));
-        for part_name in [
-            "[Content_Types].xml",
-            "_rels/.rels",
-            "docProps/core.xml",
-            "ppt/presentation.xml",
-            "ppt/_rels/presentation.xml.rels",
-            "ppt/slideMasters/slideMaster1.xml",
-            "ppt/slideMasters/_rels/slideMaster1.xml.rels",
-            "ppt/slideLayouts/slideLayout1.xml",
-            "ppt/slideLayouts/_rels/slideLayout1.xml.rels",
-            "ppt/theme/theme1.xml",
-            "ppt/slides/slide1.xml",
-            "ppt/slides/_rels/slide1.xml.rels",
-            "ppt/media/image1.png",
-        ] {
-            assert!(bytes.windows(part_name.len()).any(|w| w == part_name.as_bytes()), "missing {part_name}");
-        }
-    }
-
-    #[test]
-    pub fn pptx_slide_has_title_body_and_images_in_order() {
-        let p = sample_page();
-        let bytes = pptx(&[p], "Deck");
-        let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
-        assert!(slide_xml.contains("name=\"Title 2\""));
-        assert!(slide_xml.contains("txBox=\"1\""));
-        assert!(slide_xml.contains("Q3 Business Update"));
-        assert!(slide_xml.contains("name=\"TextBox 3\""));
-        assert!(slide_xml.contains("Revenue grew 25%"));
-        assert!(slide_xml.contains("<p:pic>"));
-        assert!(slide_xml.contains("<a:blip r:embed=\"rIdImg1\"/>"));
-        assert!(!slide_xml.contains("<p:ph"), "pure text boxes avoid placeholder inheritance repair warnings: {slide_xml}");
-
-        let rels_xml = part(&bytes, "ppt/slides/_rels/slide1.xml.rels");
-        assert!(rels_xml.contains("Target=\"../media/image1.png\""));
-        assert!(rels_xml.contains("Target=\"../slideLayouts/slideLayout1.xml\""));
-    }
-
-    #[test]
-    pub fn pptx_text_colour_and_formatting() {
-        let p = sample_page();
-        let bytes = pptx(&[p], "Deck");
-        let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
-        assert!(slide_xml.contains("sz=\"2800\""));
-        assert!(slide_xml.contains("b=\"1\""));
-        assert!(slide_xml.contains("<a:srgbClr val=\"1A334D\"/>"));
-        assert!(slide_xml.contains("i=\"1\""));
-    }
-
-    /// Every entry of the package in order: (name, uncompressed bytes), read from the local
-    /// headers the way an unzipper walks them, so a broken structure fails here.
-    fn entries(zip: &[u8]) -> Vec<(String, Vec<u8>)> {
-        let at = |i: usize, n: usize| zip[i..i + n].iter().rev().fold(0usize, |v, b| v << 8 | *b as usize);
-        let mut out = Vec::new();
-        let mut i = 0;
-        while zip[i..].starts_with(b"PK\x03\x04") {
-            let (method, size, raw, name_len, extra) = (at(i + 8, 2), at(i + 18, 4), at(i + 22, 4), at(i + 26, 2), at(i + 28, 2));
-            let data = i + 30 + name_len + extra;
-            let name = String::from_utf8(zip[i + 30..i + 30 + name_len].to_vec()).expect("UTF-8 name");
-            let body = &zip[data..data + size];
-            let bytes = match method {
-                0 => body.to_vec(),
-                8 => {
-                    let mut v = Vec::new();
-                    std::io::Read::read_to_end(&mut flate2::read::DeflateDecoder::new(body), &mut v).expect("inflates");
-                    v
-                }
-                m => panic!("{name}: unexpected method {m}"),
-            };
-            assert_eq!(bytes.len(), raw, "{name}: uncompressed size");
-            out.push((name, bytes));
-            i = data + size;
-        }
-        assert!(zip[i..].starts_with(b"PK\x01\x02"), "the central directory follows the entries");
-        out
-    }
-
-    /// Checks that every start tag is closed by the matching end tag (text is escaped, so a
-    /// `<` always starts markup). Catches a typo such as `<a:lnR>…</a:lnL>`.
-    fn assert_tags_balance(name: &str, xml: &str) {
-        let mut stack: Vec<&str> = Vec::new();
-        for chunk in xml.split('<').skip(1) {
-            let tag = chunk.split('>').next().unwrap_or_default();
-            if tag.starts_with('?') {
-                continue;
-            }
-            if let Some(close) = tag.strip_prefix('/') {
-                assert_eq!(stack.pop(), Some(close.trim()), "{name}: </{close}> closes the wrong element");
-            } else if !tag.ends_with('/') {
-                stack.push(tag.split_whitespace().next().unwrap_or_default());
-            }
-        }
-        assert!(stack.is_empty(), "{name}: unclosed {stack:?}");
-    }
-
-    #[test]
-    fn pptx_package_parts_are_complete_and_consistent() {
-        let cell = |t: &str, x: f64, y: f64| Block {
-            text: t.into(),
-            rect: [x, y, x + 100.0, y + 14.0],
-            size: 12.0,
-            bold: false,
-            italic: false,
-            color: [0.0; 3],
-            rotation: 0.0,
-            space_around: [false; 2],
-        };
-        let table_page = Page {
-            width: 612.0,
-            height: 792.0,
-            blocks: vec![
-                cell("Metric", 72.0, 400.0),
-                cell("Value", 200.0, 400.0),
-                cell("Growth", 72.0, 360.0),
-                cell("+9%", 200.0, 360.0),
-                cell("Target", 72.0, 320.0),
-                cell("100%", 200.0, 320.0),
-            ],
-            images: Vec::new(),
-            background: None,
-        };
-        let bytes = pptx(&[sample_page(), table_page], "Two");
-        let parts = entries(&bytes);
-        assert_eq!(parts.first().map(|p| p.0.as_str()), Some("[Content_Types].xml"), "content types come first");
-        let names: std::collections::HashSet<&str> = parts.iter().map(|p| p.0.as_str()).collect();
-        assert_eq!(names.len(), parts.len(), "no duplicate parts");
-        for required in [
-            "[Content_Types].xml",
-            "_rels/.rels",
-            "ppt/presentation.xml",
-            "ppt/_rels/presentation.xml.rels",
-            "ppt/slideMasters/slideMaster1.xml",
-            "ppt/slideMasters/_rels/slideMaster1.xml.rels",
-            "ppt/slideLayouts/slideLayout1.xml",
-            "ppt/slideLayouts/_rels/slideLayout1.xml.rels",
-            "ppt/theme/theme1.xml",
-            "ppt/slides/slide1.xml",
-            "ppt/slides/_rels/slide1.xml.rels",
-            "ppt/slides/slide2.xml",
-            "ppt/slides/_rels/slide2.xml.rels",
-            "ppt/media/image1.png",
-        ] {
-            assert!(names.contains(required), "missing {required}");
-        }
-        let text = |n: &str| String::from_utf8(parts.iter().find(|p| p.0 == n).map(|p| p.1.clone()).unwrap_or_default()).expect("UTF-8 XML");
-        for (name, body) in &parts {
-            if name.ends_with(".xml") || name.ends_with(".rels") {
-                assert!(body.starts_with(b"<?xml"), "{name} is XML");
-                assert_tags_balance(name, &text(name));
-            }
-        }
-        assert!(text("ppt/slides/slide2.xml").contains("<a:tbl>"), "the second slide carries the table");
-        // Text boxes, not placeholders: the blank layout defines none to inherit from.
-        for slide in ["ppt/slides/slide1.xml", "ppt/slides/slide2.xml"] {
-            assert!(!text(slide).contains("<p:ph"), "{slide} uses no placeholders");
-        }
-        // Every override names a part that exists, and every XML part has a content type.
-        let types = text("[Content_Types].xml");
-        for chunk in types.split("PartName=\"/").skip(1) {
-            let part = chunk.split('"').next().unwrap_or_default();
-            assert!(names.contains(part), "override for missing part {part}");
-        }
-        for slide in ["ppt/slides/slide1.xml", "ppt/slides/slide2.xml", "ppt/presentation.xml", "ppt/theme/theme1.xml"] {
-            assert!(types.contains(&format!("PartName=\"/{slide}\"")), "{slide} has a content type");
-        }
-        // Relationship targets resolve to parts in the package.
-        for (rels, base) in [
-            ("_rels/.rels", ""),
-            ("ppt/_rels/presentation.xml.rels", "ppt/"),
-            ("ppt/slides/_rels/slide1.xml.rels", "ppt/slides/"),
-            ("ppt/slides/_rels/slide2.xml.rels", "ppt/slides/"),
-            ("ppt/slideMasters/_rels/slideMaster1.xml.rels", "ppt/slideMasters/"),
-            ("ppt/slideLayouts/_rels/slideLayout1.xml.rels", "ppt/slideLayouts/"),
-        ] {
-            for chunk in text(rels).split("Target=\"").skip(1) {
-                let target = chunk.split('"').next().unwrap_or_default();
-                let mut path: Vec<&str> = base.split('/').filter(|s| !s.is_empty()).collect();
-                for seg in target.split('/') {
-                    if seg == ".." {
-                        path.pop();
-                    } else {
-                        path.push(seg);
-                    }
-                }
-                let resolved = path.join("/");
-                assert!(names.contains(resolved.as_str()), "{rels}: target {target} is missing");
-            }
-        }
-        // The theme's font scheme carries the schema-required latin, ea and cs faces.
-        let theme = text("ppt/theme/theme1.xml");
-        for font in ["majorFont", "minorFont"] {
-            let inner = theme.split(&format!("<a:{font}>")).nth(1).and_then(|r| r.split(&format!("</a:{font}>")).next()).unwrap_or_default();
-            assert!(inner.contains("<a:latin ") && inner.contains("<a:ea ") && inner.contains("<a:cs "), "{font}: {inner}");
-        }
-        assert!(text("ppt/presentation.xml").contains("r:id=\"rIdSld2\""));
-    }
-
-    #[test]
-    fn hostile_sizes_do_not_overflow_the_slide_position() {
-        let huge = |text: &str, size: f64, y: f64| Block {
-            text: text.into(),
-            rect: [72.0, y, 500.0, y + 10.0],
-            size,
-            bold: false,
-            italic: false,
-            color: [0.0; 3],
-            rotation: 0.0,
-            space_around: [false; 2],
-        };
-        let mut blocks = vec![huge("Title", f64::MAX, 500.0)];
-        for k in 0..40 {
-            blocks.push(huge(&"word ".repeat(10_000), 1e300, 400.0 - k as f64));
-            blocks.push(huge("nan", f64::NAN, 300.0 - k as f64));
-            blocks.push(huge("inf", f64::INFINITY, 200.0 - k as f64));
-        }
-        let images = (0..40)
-            .map(|k| Image {
-                ext: "png",
-                bytes: [0; 4].as_slice().into(),
-                rect: [0.0, -1e300, 1e-300, 1e300 - k as f64],
-                size: [1.0, 1.0],
-                rotation: 0.0,
-            })
-            .collect();
-        let p = Page { width: f64::MAX, height: f64::NAN, blocks, images, background: None };
-        let bytes = pptx(&[p], "Hostile");
-        let slide = part(&bytes, "ppt/slides/slide1.xml");
-        assert!(slide.contains("Title") && slide.contains("<p:pic>"), "the slide is still written");
-        assert!(!slide.contains("y=\"-"), "positions never wrap negative");
-        assert!(!slide.contains("<p:ph"), "text boxes, not placeholders");
-    }
-
-    #[test]
-    pub fn pptx_empty_pages_produce_valid_slide() {
-        let bytes = pptx(&[], "Blank");
-        assert!(bytes.starts_with(b"PK"));
-        let pres_xml = part(&bytes, "ppt/presentation.xml");
-        assert!(pres_xml.contains("<p:sldId id=\"256\" r:id=\"rIdSld1\"/>"));
-        let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
-        assert!(slide_xml.contains("<p:spTree>"));
-    }
-
-    #[test]
-    fn pptx_slide_dimensions_and_clamping() {
-        // Known dimensions: 720x540 pt (10x7.5 in) = 9144000x6858000 EMU
-        let p = Page { width: 720.0, height: 540.0, ..Page::default() };
-        let bytes = pptx(&[p], "Known Dimensions");
-        let pres_xml = part(&bytes, "ppt/presentation.xml");
-        assert!(pres_xml.contains("<p:sldSz cx=\"9144000\" cy=\"6858000\"/>"), "{pres_xml}");
-
-        // Tiny page (10x10 pt) clamps to PowerPoint minimum of 1 inch (914400 EMU)
-        let tiny = Page { width: 10.0, height: 10.0, ..Page::default() };
-        let tiny_bytes = pptx(&[tiny], "Tiny");
-        let tiny_pres = part(&tiny_bytes, "ppt/presentation.xml");
-        assert!(tiny_pres.contains("<p:sldSz cx=\"914400\" cy=\"914400\"/>"), "{tiny_pres}");
-
-        // Poster page (10000x10000 pt) clamps to PowerPoint maximum of 56 inches (51206400 EMU)
-        let poster = Page { width: 10_000.0, height: 10_000.0, ..Page::default() };
-        let poster_bytes = pptx(&[poster], "Poster");
-        let poster_pres = part(&poster_bytes, "ppt/presentation.xml");
-        assert!(poster_pres.contains("<p:sldSz cx=\"51206400\" cy=\"51206400\"/>"), "{poster_pres}");
-
-        // Non-finite dimensions fall back to default
-        let nan_page = Page { width: f64::NAN, height: -1.0, ..Page::default() };
-        let nan_bytes = pptx(&[nan_page], "NaN");
-        let nan_pres = part(&nan_bytes, "ppt/presentation.xml");
-        assert!(nan_pres.contains("<p:sldSz cx=\"9144000\" cy=\"6858000\"/>"), "{nan_pres}");
-    }
-
-    #[test]
-    fn pptx_table_cell_with_largest_font_stays_in_table_and_not_in_title() {
-        let cell = |t: &str, x: f64, y: f64, w: f64, sz: f64| Block {
-            text: t.into(),
-            rect: [x, y, x + w, y + 14.0],
-            size: sz,
-            bold: false,
-            italic: false,
-            color: [0.0; 3],
-            rotation: 0.0,
-            space_around: [false; 2],
-        };
-        let p = Page {
-            width: 720.0,
-            height: 540.0,
-            blocks: vec![
-                // Heading outside the table (short width, does not span table columns)
-                Block {
-                    text: "Monthly Summary".into(),
-                    rect: [50.0, 480.0, 150.0, 500.0],
-                    size: 20.0,
-                    bold: true,
-                    italic: false,
-                    color: [0.0; 3],
-                    rotation: 0.0,
-                    space_around: [false; 2],
-                },
-                // Table where one cell has a very large number (e.g. 36 pt callout in the table)
-                cell("Metric", 72.0, 400.0, 100.0, 12.0),
-                cell("Value", 200.0, 400.0, 100.0, 12.0),
-                cell("Growth", 72.0, 360.0, 100.0, 12.0),
-                cell("+99%", 200.0, 360.0, 100.0, 36.0),
-                cell("Target", 72.0, 320.0, 100.0, 12.0),
-                cell("100%", 200.0, 320.0, 100.0, 12.0),
-            ],
-            images: Vec::new(),
-            background: None,
-        };
-        let bytes = pptx(&[p], "Table Check");
-        let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
-        // Title should be the block outside the table ("Monthly Summary"), not the "+99%" cell
-        assert!(slide_xml.contains("Monthly Summary"));
-        assert!(slide_xml.contains("name=\"Title 2\""));
-        // The table must contain both the cell and explicit borders
-        assert!(slide_xml.contains("<a:tbl>"));
-        assert!(slide_xml.contains("+99%"));
-        assert!(slide_xml.contains("<a:tcPr><a:lnL w=\"12700\" cmpd=\"s\">"));
-    }
-
-    #[test]
-    fn pptx_opens_in_libreoffice() {
-        let p = sample_page();
-        let bytes = pptx(&[p], "LibreOffice Check");
-        let dir = std::env::temp_dir().join(format!("pdfcraft-pptx-lo-{}", std::process::id()));
-        let _ = std::fs::remove_dir_all(&dir);
-        let _ = std::fs::create_dir_all(&dir);
-        let pptx_path = dir.join("test.pptx");
-        std::fs::write(&pptx_path, &bytes).unwrap();
-
-        for cmd in ["libreoffice", "soffice"] {
-            let status = std::process::Command::new(cmd).args(["--headless", "--convert-to", "pdf", "--outdir"]).arg(&dir).arg(&pptx_path).status();
-            if status.is_ok_and(|st| st.success()) {
-                assert!(dir.join("test.pdf").is_file(), "LibreOffice produced test.pdf");
-                break;
-            }
-        }
-        let _ = std::fs::remove_dir_all(&dir);
-    }
-}
+mod tests;
diff --git a/crates/export/src/pptx/tests.rs b/crates/export/src/pptx/tests.rs
new file mode 100644
index 000000000..2e1c1bd04
--- /dev/null
+++ b/crates/export/src/pptx/tests.rs
@@ -0,0 +1,393 @@
+use super::*;
+use crate::Block;
+use crate::tests::part;
+
+fn sample_page() -> Page {
+    Page {
+        width: 720.0,
+        height: 540.0,
+        blocks: vec![
+            Block {
+                text: "Q3 Business Update".into(),
+                rect: [72.0, 460.0, 500.0, 500.0],
+                size: 28.0,
+                bold: true,
+                italic: false,
+                color: [0.1, 0.2, 0.3],
+                rotation: 0.0,
+                space_around: [false; 2],
+            },
+            Block {
+                text: "Revenue grew 25% year over year across all regions.".into(),
+                rect: [72.0, 380.0, 500.0, 410.0],
+                size: 14.0,
+                bold: false,
+                italic: false,
+                color: [0.0; 3],
+                rotation: 0.0,
+                space_around: [false; 2],
+            },
+            Block {
+                text: "Operational expenses remained flat.".into(),
+                rect: [72.0, 340.0, 500.0, 370.0],
+                size: 14.0,
+                bold: false,
+                italic: true,
+                color: [0.0; 3],
+                rotation: 0.0,
+                space_around: [false; 2],
+            },
+        ],
+        images: vec![Image {
+            ext: "png",
+            bytes: b"\x89PNG\r\n\x1a\n\0\0\0\rIHDR\0\0\0\x02\0\0\0\x03".as_slice().into(),
+            rect: [72.0, 150.0, 300.0, 300.0],
+            size: [228.0, 150.0],
+            rotation: 0.0,
+        }],
+        background: None,
+    }
+}
+
+#[test]
+pub fn pptx_is_a_presentationml_package() {
+    let p = sample_page();
+    let bytes = pptx(&[p], "Executive Deck");
+    assert!(bytes.starts_with(b"PK"));
+    for part_name in [
+        "[Content_Types].xml",
+        "_rels/.rels",
+        "docProps/core.xml",
+        "ppt/presentation.xml",
+        "ppt/_rels/presentation.xml.rels",
+        "ppt/slideMasters/slideMaster1.xml",
+        "ppt/slideMasters/_rels/slideMaster1.xml.rels",
+        "ppt/slideLayouts/slideLayout1.xml",
+        "ppt/slideLayouts/_rels/slideLayout1.xml.rels",
+        "ppt/theme/theme1.xml",
+        "ppt/slides/slide1.xml",
+        "ppt/slides/_rels/slide1.xml.rels",
+        "ppt/media/image1.png",
+    ] {
+        assert!(bytes.windows(part_name.len()).any(|w| w == part_name.as_bytes()), "missing {part_name}");
+    }
+}
+
+#[test]
+pub fn pptx_slide_has_title_body_and_images_in_order() {
+    let p = sample_page();
+    let bytes = pptx(&[p], "Deck");
+    let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
+    assert!(slide_xml.contains("name=\"Title 2\""));
+    assert!(slide_xml.contains("txBox=\"1\""));
+    assert!(slide_xml.contains("Q3 Business Update"));
+    assert!(slide_xml.contains("name=\"TextBox 3\""));
+    assert!(slide_xml.contains("Revenue grew 25%"));
+    assert!(slide_xml.contains("<p:pic>"));
+    assert!(slide_xml.contains("<a:blip r:embed=\"rIdImg1\"/>"));
+    assert!(!slide_xml.contains("<p:ph"), "pure text boxes avoid placeholder inheritance repair warnings: {slide_xml}");
+
+    let rels_xml = part(&bytes, "ppt/slides/_rels/slide1.xml.rels");
+    assert!(rels_xml.contains("Target=\"../media/image1.png\""));
+    assert!(rels_xml.contains("Target=\"../slideLayouts/slideLayout1.xml\""));
+}
+
+#[test]
+pub fn pptx_text_colour_and_formatting() {
+    let p = sample_page();
+    let bytes = pptx(&[p], "Deck");
+    let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
+    assert!(slide_xml.contains("sz=\"2800\""));
+    assert!(slide_xml.contains("b=\"1\""));
+    assert!(slide_xml.contains("<a:srgbClr val=\"1A334D\"/>"));
+    assert!(slide_xml.contains("i=\"1\""));
+}
+
+/// Every entry of the package in order: (name, uncompressed bytes), read from the local
+/// headers the way an unzipper walks them, so a broken structure fails here.
+fn entries(zip: &[u8]) -> Vec<(String, Vec<u8>)> {
+    let at = |i: usize, n: usize| zip[i..i + n].iter().rev().fold(0usize, |v, b| v << 8 | *b as usize);
+    let mut out = Vec::new();
+    let mut i = 0;
+    while zip[i..].starts_with(b"PK\x03\x04") {
+        let (method, size, raw, name_len, extra) = (at(i + 8, 2), at(i + 18, 4), at(i + 22, 4), at(i + 26, 2), at(i + 28, 2));
+        let data = i + 30 + name_len + extra;
+        let name = String::from_utf8(zip[i + 30..i + 30 + name_len].to_vec()).expect("UTF-8 name");
+        let body = &zip[data..data + size];
+        let bytes = match method {
+            0 => body.to_vec(),
+            8 => {
+                let mut v = Vec::new();
+                std::io::Read::read_to_end(&mut flate2::read::DeflateDecoder::new(body), &mut v).expect("inflates");
+                v
+            }
+            m => panic!("{name}: unexpected method {m}"),
+        };
+        assert_eq!(bytes.len(), raw, "{name}: uncompressed size");
+        out.push((name, bytes));
+        i = data + size;
+    }
+    assert!(zip[i..].starts_with(b"PK\x01\x02"), "the central directory follows the entries");
+    out
+}
+
+/// Checks that every start tag is closed by the matching end tag (text is escaped, so a
+/// `<` always starts markup). Catches a typo such as `<a:lnR>…</a:lnL>`.
+fn assert_tags_balance(name: &str, xml: &str) {
+    let mut stack: Vec<&str> = Vec::new();
+    for chunk in xml.split('<').skip(1) {
+        let tag = chunk.split('>').next().unwrap_or_default();
+        if tag.starts_with('?') {
+            continue;
+        }
+        if let Some(close) = tag.strip_prefix('/') {
+            assert_eq!(stack.pop(), Some(close.trim()), "{name}: </{close}> closes the wrong element");
+        } else if !tag.ends_with('/') {
+            stack.push(tag.split_whitespace().next().unwrap_or_default());
+        }
+    }
+    assert!(stack.is_empty(), "{name}: unclosed {stack:?}");
+}
+
+#[test]
+fn pptx_package_parts_are_complete_and_consistent() {
+    let cell = |t: &str, x: f64, y: f64| Block {
+        text: t.into(),
+        rect: [x, y, x + 100.0, y + 14.0],
+        size: 12.0,
+        bold: false,
+        italic: false,
+        color: [0.0; 3],
+        rotation: 0.0,
+        space_around: [false; 2],
+    };
+    let table_page = Page {
+        width: 612.0,
+        height: 792.0,
+        blocks: vec![
+            cell("Metric", 72.0, 400.0),
+            cell("Value", 200.0, 400.0),
+            cell("Growth", 72.0, 360.0),
+            cell("+9%", 200.0, 360.0),
+            cell("Target", 72.0, 320.0),
+            cell("100%", 200.0, 320.0),
+        ],
+        images: Vec::new(),
+        background: None,
+    };
+    let bytes = pptx(&[sample_page(), table_page], "Two");
+    let parts = entries(&bytes);
+    assert_eq!(parts.first().map(|p| p.0.as_str()), Some("[Content_Types].xml"), "content types come first");
+    let names: std::collections::HashSet<&str> = parts.iter().map(|p| p.0.as_str()).collect();
+    assert_eq!(names.len(), parts.len(), "no duplicate parts");
+    for required in [
+        "[Content_Types].xml",
+        "_rels/.rels",
+        "ppt/presentation.xml",
+        "ppt/_rels/presentation.xml.rels",
+        "ppt/slideMasters/slideMaster1.xml",
+        "ppt/slideMasters/_rels/slideMaster1.xml.rels",
+        "ppt/slideLayouts/slideLayout1.xml",
+        "ppt/slideLayouts/_rels/slideLayout1.xml.rels",
+        "ppt/theme/theme1.xml",
+        "ppt/slides/slide1.xml",
+        "ppt/slides/_rels/slide1.xml.rels",
+        "ppt/slides/slide2.xml",
+        "ppt/slides/_rels/slide2.xml.rels",
+        "ppt/media/image1.png",
+    ] {
+        assert!(names.contains(required), "missing {required}");
+    }
+    let text = |n: &str| String::from_utf8(parts.iter().find(|p| p.0 == n).map(|p| p.1.clone()).unwrap_or_default()).expect("UTF-8 XML");
+    for (name, body) in &parts {
+        if name.ends_with(".xml") || name.ends_with(".rels") {
+            assert!(body.starts_with(b"<?xml"), "{name} is XML");
+            assert_tags_balance(name, &text(name));
+        }
+    }
+    assert!(text("ppt/slides/slide2.xml").contains("<a:tbl>"), "the second slide carries the table");
+    // Text boxes, not placeholders: the blank layout defines none to inherit from.
+    for slide in ["ppt/slides/slide1.xml", "ppt/slides/slide2.xml"] {
+        assert!(!text(slide).contains("<p:ph"), "{slide} uses no placeholders");
+    }
+    // Every override names a part that exists, and every XML part has a content type.
+    let types = text("[Content_Types].xml");
+    for chunk in types.split("PartName=\"/").skip(1) {
+        let part = chunk.split('"').next().unwrap_or_default();
+        assert!(names.contains(part), "override for missing part {part}");
+    }
+    for slide in ["ppt/slides/slide1.xml", "ppt/slides/slide2.xml", "ppt/presentation.xml", "ppt/theme/theme1.xml"] {
+        assert!(types.contains(&format!("PartName=\"/{slide}\"")), "{slide} has a content type");
+    }
+    // Relationship targets resolve to parts in the package.
+    for (rels, base) in [
+        ("_rels/.rels", ""),
+        ("ppt/_rels/presentation.xml.rels", "ppt/"),
+        ("ppt/slides/_rels/slide1.xml.rels", "ppt/slides/"),
+        ("ppt/slides/_rels/slide2.xml.rels", "ppt/slides/"),
+        ("ppt/slideMasters/_rels/slideMaster1.xml.rels", "ppt/slideMasters/"),
+        ("ppt/slideLayouts/_rels/slideLayout1.xml.rels", "ppt/slideLayouts/"),
+    ] {
+        for chunk in text(rels).split("Target=\"").skip(1) {
+            let target = chunk.split('"').next().unwrap_or_default();
+            let mut path: Vec<&str> = base.split('/').filter(|s| !s.is_empty()).collect();
+            for seg in target.split('/') {
+                if seg == ".." {
+                    path.pop();
+                } else {
+                    path.push(seg);
+                }
+            }
+            let resolved = path.join("/");
+            assert!(names.contains(resolved.as_str()), "{rels}: target {target} is missing");
+        }
+    }
+    // The theme's font scheme carries the schema-required latin, ea and cs faces.
+    let theme = text("ppt/theme/theme1.xml");
+    for font in ["majorFont", "minorFont"] {
+        let inner = theme.split(&format!("<a:{font}>")).nth(1).and_then(|r| r.split(&format!("</a:{font}>")).next()).unwrap_or_default();
+        assert!(inner.contains("<a:latin ") && inner.contains("<a:ea ") && inner.contains("<a:cs "), "{font}: {inner}");
+    }
+    assert!(text("ppt/presentation.xml").contains("r:id=\"rIdSld2\""));
+}
+
+#[test]
+fn hostile_sizes_do_not_overflow_the_slide_position() {
+    let huge = |text: &str, size: f64, y: f64| Block {
+        text: text.into(),
+        rect: [72.0, y, 500.0, y + 10.0],
+        size,
+        bold: false,
+        italic: false,
+        color: [0.0; 3],
+        rotation: 0.0,
+        space_around: [false; 2],
+    };
+    let mut blocks = vec![huge("Title", f64::MAX, 500.0)];
+    for k in 0..40 {
+        blocks.push(huge(&"word ".repeat(10_000), 1e300, 400.0 - k as f64));
+        blocks.push(huge("nan", f64::NAN, 300.0 - k as f64));
+        blocks.push(huge("inf", f64::INFINITY, 200.0 - k as f64));
+    }
+    let images = (0..40)
+        .map(|k| Image {
+            ext: "png",
+            bytes: [0; 4].as_slice().into(),
+            rect: [0.0, -1e300, 1e-300, 1e300 - k as f64],
+            size: [1.0, 1.0],
+            rotation: 0.0,
+        })
+        .collect();
+    let p = Page { width: f64::MAX, height: f64::NAN, blocks, images, background: None };
+    let bytes = pptx(&[p], "Hostile");
+    let slide = part(&bytes, "ppt/slides/slide1.xml");
+    assert!(slide.contains("Title") && slide.contains("<p:pic>"), "the slide is still written");
+    assert!(!slide.contains("y=\"-"), "positions never wrap negative");
+    assert!(!slide.contains("<p:ph"), "text boxes, not placeholders");
+}
+
+#[test]
+pub fn pptx_empty_pages_produce_valid_slide() {
+    let bytes = pptx(&[], "Blank");
+    assert!(bytes.starts_with(b"PK"));
+    let pres_xml = part(&bytes, "ppt/presentation.xml");
+    assert!(pres_xml.contains("<p:sldId id=\"256\" r:id=\"rIdSld1\"/>"));
+    let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
+    assert!(slide_xml.contains("<p:spTree>"));
+}
+
+#[test]
+fn pptx_slide_dimensions_and_clamping() {
+    // Known dimensions: 720x540 pt (10x7.5 in) = 9144000x6858000 EMU
+    let p = Page { width: 720.0, height: 540.0, ..Page::default() };
+    let bytes = pptx(&[p], "Known Dimensions");
+    let pres_xml = part(&bytes, "ppt/presentation.xml");
+    assert!(pres_xml.contains("<p:sldSz cx=\"9144000\" cy=\"6858000\"/>"), "{pres_xml}");
+
+    // Tiny page (10x10 pt) clamps to PowerPoint minimum of 1 inch (914400 EMU)
+    let tiny = Page { width: 10.0, height: 10.0, ..Page::default() };
+    let tiny_bytes = pptx(&[tiny], "Tiny");
+    let tiny_pres = part(&tiny_bytes, "ppt/presentation.xml");
+    assert!(tiny_pres.contains("<p:sldSz cx=\"914400\" cy=\"914400\"/>"), "{tiny_pres}");
+
+    // Poster page (10000x10000 pt) clamps to PowerPoint maximum of 56 inches (51206400 EMU)
+    let poster = Page { width: 10_000.0, height: 10_000.0, ..Page::default() };
+    let poster_bytes = pptx(&[poster], "Poster");
+    let poster_pres = part(&poster_bytes, "ppt/presentation.xml");
+    assert!(poster_pres.contains("<p:sldSz cx=\"51206400\" cy=\"51206400\"/>"), "{poster_pres}");
+
+    // Non-finite dimensions fall back to default
+    let nan_page = Page { width: f64::NAN, height: -1.0, ..Page::default() };
+    let nan_bytes = pptx(&[nan_page], "NaN");
+    let nan_pres = part(&nan_bytes, "ppt/presentation.xml");
+    assert!(nan_pres.contains("<p:sldSz cx=\"9144000\" cy=\"6858000\"/>"), "{nan_pres}");
+}
+
+#[test]
+fn pptx_table_cell_with_largest_font_stays_in_table_and_not_in_title() {
+    let cell = |t: &str, x: f64, y: f64, w: f64, sz: f64| Block {
+        text: t.into(),
+        rect: [x, y, x + w, y + 14.0],
+        size: sz,
+        bold: false,
+        italic: false,
+        color: [0.0; 3],
+        rotation: 0.0,
+        space_around: [false; 2],
+    };
+    let p = Page {
+        width: 720.0,
+        height: 540.0,
+        blocks: vec![
+            // Heading outside the table (short width, does not span table columns)
+            Block {
+                text: "Monthly Summary".into(),
+                rect: [50.0, 480.0, 150.0, 500.0],
+                size: 20.0,
+                bold: true,
+                italic: false,
+                color: [0.0; 3],
+                rotation: 0.0,
+                space_around: [false; 2],
+            },
+            // Table where one cell has a very large number (e.g. 36 pt callout in the table)
+            cell("Metric", 72.0, 400.0, 100.0, 12.0),
+            cell("Value", 200.0, 400.0, 100.0, 12.0),
+            cell("Growth", 72.0, 360.0, 100.0, 12.0),
+            cell("+99%", 200.0, 360.0, 100.0, 36.0),
+            cell("Target", 72.0, 320.0, 100.0, 12.0),
+            cell("100%", 200.0, 320.0, 100.0, 12.0),
+        ],
+        images: Vec::new(),
+        background: None,
+    };
+    let bytes = pptx(&[p], "Table Check");
+    let slide_xml = part(&bytes, "ppt/slides/slide1.xml");
+    // Title should be the block outside the table ("Monthly Summary"), not the "+99%" cell
+    assert!(slide_xml.contains("Monthly Summary"));
+    assert!(slide_xml.contains("name=\"Title 2\""));
+    // The table must contain both the cell and explicit borders
+    assert!(slide_xml.contains("<a:tbl>"));
+    assert!(slide_xml.contains("+99%"));
+    assert!(slide_xml.contains("<a:tcPr><a:lnL w=\"12700\" cmpd=\"s\">"));
+}
+
+#[test]
+fn pptx_opens_in_libreoffice() {
+    let p = sample_page();
+    let bytes = pptx(&[p], "LibreOffice Check");
+    let dir = std::env::temp_dir().join(format!("pdfcraft-pptx-lo-{}", std::process::id()));
+    let _ = std::fs::remove_dir_all(&dir);
+    let _ = std::fs::create_dir_all(&dir);
+    let pptx_path = dir.join("test.pptx");
+    std::fs::write(&pptx_path, &bytes).unwrap();
+
+    for cmd in ["libreoffice", "soffice"] {
+        let status = std::process::Command::new(cmd).args(["--headless", "--convert-to", "pdf", "--outdir"]).arg(&dir).arg(&pptx_path).status();
+        if status.is_ok_and(|st| st.success()) {
+            assert!(dir.join("test.pdf").is_file(), "LibreOffice produced test.pdf");
+            break;
+        }
+    }
+    let _ = std::fs::remove_dir_all(&dir);
+}