diff --git a/Cargo.lock b/Cargo.lock
index 959c84fe..5fca5c19 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1754,6 +1754,12 @@ dependencies = [
  "regex",
 ]
 
+[[package]]
+name = "path-slash"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3cacbb3c4ff353b534a67fb8d7524d00229da4cb1dc8c79f4db96e375ab5b619"
+
 [[package]]
 name = "percent-encoding"
 version = "2.1.0"
@@ -2461,6 +2467,7 @@ dependencies = [
  "lazy_static",
  "library",
  "link_checker",
+ "path-slash",
  "rayon",
  "relative-path",
  "sass-rs",
diff --git a/components/library/src/library.rs b/components/library/src/library.rs
index b933f8b6..362ca5e5 100644
--- a/components/library/src/library.rs
+++ b/components/library/src/library.rs
@@ -154,6 +154,16 @@ impl Library {
                     .push(section.file.path.clone());
             }
 
+            // populate translations if necessary
+            if self.is_multilingual {
+                self.translations
+                    .entry(section.file.canonical.clone())
+                    .and_modify(|trans| {
+                        trans.insert(key);
+                    })
+                    .or_insert(set![key]);
+            };
+
             // Index has no ancestors, no need to go through it
             if section.is_index() {
                 ancestors.insert(section.file.path.clone(), vec![]);
@@ -178,15 +188,7 @@ impl Library {
             }
             ancestors.insert(section.file.path.clone(), parents);
 
-            // populate translations if necessary
-            if self.is_multilingual {
-                self.translations
-                    .entry(section.file.canonical.clone())
-                    .and_modify(|trans| {
-                        trans.insert(key);
-                    })
-                    .or_insert(set![key]);
-            };
+
         }
 
         for (key, page) in &mut self.pages {
diff --git a/components/site/Cargo.toml b/components/site/Cargo.toml
index 51fa4907..eb90d9c8 100644
--- a/components/site/Cargo.toml
+++ b/components/site/Cargo.toml
@@ -29,3 +29,4 @@ link_checker = { path = "../link_checker" }
 
 [dev-dependencies]
 tempfile = "3"
+path-slash = "0.1.4"
diff --git a/components/site/tests/common.rs b/components/site/tests/common.rs
index 24431706..a6858a3b 100644
--- a/components/site/tests/common.rs
+++ b/components/site/tests/common.rs
@@ -1,9 +1,11 @@
 #![allow(dead_code)]
 use std::env;
-use std::path::PathBuf;
+use std::path::{PathBuf, Path};
+use std::collections::HashMap;
 
 use site::Site;
 use tempfile::{tempdir, TempDir};
+use path_slash::PathExt;
 
 // 2 helper macros to make all the build testing more bearable
 #[macro_export]
@@ -67,3 +69,253 @@ where
     site.build().expect("Couldn't build the site");
     (site, tmp_dir, public.clone())
 }
+
+/// Finds the unified path (eg. _index.fr.md -> _index.md) and
+/// potential language (if not default) associated with a path
+/// When the path is not a markdown file (.md), None is returned
+/// Strips base_dir from the start of path
+fn find_lang_for(entry: &Path, base_dir: &Path) -> Option<(String, Option<String>)> {
+    let ext = entry.extension();
+    if ext.is_none() {
+        // Not a markdown file (no extension), skip
+        return None;
+    }
+    let ext = ext.unwrap();
+    if ext != "md" {
+        // Not a markdown file, skip
+        return None;
+    }
+    let mut no_ext = entry.to_path_buf();
+    let stem = entry.file_stem().unwrap();
+    // Remove .md
+    no_ext.pop();
+    no_ext.push(stem);
+    if let Some(lang) = no_ext.extension() {
+        let stem = no_ext.file_stem();
+        // Remove lang
+        let mut unified_path = no_ext.clone();
+        unified_path.pop();
+        // Readd stem with .md added
+        unified_path.push(&format!("{}.md", stem.unwrap().to_str().unwrap()));
+        let unified_path_str = match unified_path.strip_prefix(base_dir)  {
+			Ok(path_without_prefix) => {path_without_prefix.to_slash_lossy()}
+			_ => {unified_path.to_slash_lossy()}
+		};
+        return Some((unified_path_str, Some(lang.to_str().unwrap().into())));
+    } else {
+        // No lang, return no_ext directly
+		let mut no_ext_string = match no_ext.strip_prefix(base_dir)  {
+			Ok(path_without_prefix) => {path_without_prefix.to_slash_lossy()}
+			_ => {no_ext.to_slash_lossy()}
+		};
+		no_ext_string.push_str(".md");
+        return Some((no_ext_string, None));
+    }
+}
+
+/// Recursively process a folder to find translations, returning a list of every language
+/// translated for every page found. Translations for the default language are stored as "DEFAULT"
+/// TODO: This implementation does not support files with a dot inside (foo.bar.md where bar is
+/// not a language), because it requires to know what languages are enabled from config, and it's
+/// unclear how to distinguish (and what to do) between disabled language or "legit" dots
+pub fn add_translations_from(dir: &Path, strip: &Path, default: &str) -> HashMap<String, Vec<String>> {
+    let mut expected: HashMap<String, Vec<String>> = HashMap::new();
+    for entry in dir.read_dir().expect("Failed to read dir") {
+        let entry = entry.expect("Failed to read entry").path();
+        if entry.is_dir() {
+            // Recurse
+            expected.extend(add_translations_from(&entry, strip, default));
+        }
+        if let Some((unified_path, lang)) = find_lang_for(&entry, strip) {
+            if let Some(index) = expected.get_mut(&unified_path) {
+                // Insert found lang for rel_path, or DEFAULT otherwise
+                index.push(lang.unwrap_or(default.to_string()));
+            } else {
+                // rel_path is not registered yet, insert it in expected
+                expected.insert(unified_path, vec!(lang.unwrap_or(default.to_string())));
+            }
+        } else {
+            // Not a markdown file, skip
+            continue;
+        }
+    }
+    return expected;
+}
+
+/// Calculate output path for Markdown files
+/// respecting page/section `path` fields, but not aliases (yet)
+/// Returns a mapping of unified Markdown paths -> translations
+pub fn find_expected_translations(name: &str, default_language: &str) -> HashMap<String, Vec<String>> {
+    let mut path = env::current_dir().unwrap().parent().unwrap().parent().unwrap().to_path_buf();
+    path.push(name);
+    path.push("content");
+
+    // Find expected translations from content folder
+    // We remove BASEDIR/content/ from the keys so they match paths in library
+    let mut strip_prefix = path.to_str().unwrap().to_string();
+    strip_prefix.push('/');
+    add_translations_from(&path, &path, default_language)
+}
+
+/// Checks whether a given permalink has a corresponding HTML page in output folder
+pub fn ensure_output_exists(outputdir: &Path, baseurl: &str, link: &str) -> bool {
+    // Remove the baseurl as well as the remaining /, otherwise path will be interpreted
+    // as absolute.
+    let trimmed_url = link.trim_start_matches(baseurl).trim_start_matches('/');
+    let path = outputdir.join(trimmed_url);
+    path.exists()
+}
+
+pub struct Translation {
+    path: String,
+    lang: String,
+    permalink: String,
+}
+
+pub struct Translations {
+    trans: Vec<Translation>,
+}
+
+impl Translations {
+    pub fn for_path(site: &Site, path: &str) -> Translations {
+        let library = site.library.clone();
+        let library = library.read().unwrap();
+        // WORKAROUND because site.content_path is private
+        let unified_path = if let Some(page) = library.get_page(site.base_path.join("content").join(path)) {
+            page.file.canonical.clone()
+        } else if let Some(section) = library.get_section(site.base_path.join("content").join(path)) {
+            section.file.canonical.clone()
+        } else {
+            panic!("No such page or section: {}", path);
+        };
+
+        let translations = library.translations.get(&unified_path);
+        if translations.is_none() {
+            println!("Page canonical path {} is not in library translations", unified_path.display());
+            panic!("Library error");
+        }
+
+        let translations = translations
+            .unwrap()
+            .iter().map(|key| {
+                // Are we looking for a section? (no file extension here)
+                if unified_path.ends_with("_index") {
+                    //library.get_section_by_key(*key).file.relative.to_string()
+                    let section = library.get_section_by_key(*key);
+                    Translation {
+                        lang: section.lang.clone(),
+                        permalink: section.permalink.clone(),
+                        path: section.file.path.to_str().unwrap().to_string(),
+                    }
+                } else {
+                    let page = library.get_page_by_key(*key);
+                    Translation {
+                        lang: page.lang.clone(),
+                        permalink: page.permalink.clone(),
+                        path: page.file.path.to_str().unwrap().to_string(),
+                    }
+                    //library.get_page_by_key(*key).file.relative.to_string()
+                }
+            }).collect();
+
+        Translations {
+            trans: translations,
+        }
+    }
+
+    pub fn languages(&self) -> Vec<String> {
+        let mut lang: Vec<String> = self.trans.iter().map(|x| x.lang.clone()).collect();
+        lang.sort_unstable();
+        lang
+    }
+
+    pub fn permalinks(&self) -> Vec<String> {
+        let mut links: Vec<String> = self.trans.iter().map(|x| x.permalink.clone()).collect();
+        links.sort_unstable();
+        links
+    }
+
+    pub fn paths(&self) -> Vec<String> {
+        let mut paths: Vec<String> = self.trans.iter().map(|x| x.path.clone()).collect();
+        paths.sort_unstable();
+        paths
+    }
+}
+
+/// Find translations in library for a single path
+fn library_translations_lang_for(site: &Site, path: &str) -> Vec<String> {
+    let library_translations = Translations::for_path(site, path);
+    library_translations.languages()
+}
+
+/// This function takes a list of translations generated by find_expected_translations(),
+/// a site instance, and a path of a page to check that translations are the same on both sides
+pub fn ensure_translations_match(translations: &HashMap<String, Vec<String>>, site: &Site, path: &str) -> bool {
+    let library_page_translations = library_translations_lang_for(site, path);
+
+    if let Some((unified_path, _lang)) = find_lang_for(&PathBuf::from(path), Path::new("")) {
+        if let Some(page_translations) = translations.get(&unified_path) {
+            // We order both claimed translations so we can compare them
+            // library_page_translations is already ordered
+            let mut page_translations = page_translations.clone();
+            page_translations.sort_unstable();
+
+            if page_translations != library_page_translations {
+                // Some translations don't match, print some context
+                // There is a special case where the index page may be autogenerated for a lang
+                // by zola so if we are looking at the index page, library may contain more (not
+                // less) languages than our tests.
+                if unified_path == "_index.md" {
+                    for lang in &page_translations {
+                        if !library_page_translations.contains(lang) {
+                            println!("Library is missing language: {} for page {}", lang, unified_path);
+                            return false;
+                        }
+                    }
+                    // All languages from Markdown were found. We don't care if the library
+                    // auto-generated more.
+                    return true;
+                }
+                println!("Translations don't match for {}:", path);
+                println!("  - library: {:?}", library_page_translations);
+                println!("  - tests: {:?}", page_translations);
+                return false;
+            }
+            // Everything went well
+            return true;
+        } else {
+            // Should never happen because even the default language counts as a translation
+            // Reaching here means either there is a logic error in the tests themselves,
+            // or the permalinks contained a page which does not exist for some reason
+            unreachable!("Translations not found for {}", unified_path);
+        }
+    } else {
+        // None means the page does not end with .md. Only markdown pages should be passed to this function.
+        // Maybe a non-markdown path was found in site's permalinks?
+        unreachable!("{} is not a markdown page (extension not .md)", path);
+    }
+}
+
+/// For a given URL (from the permalinks), find the corresponding output page
+/// and ensure all translation permalinks are linked inside
+pub fn ensure_translations_in_output(site: &Site, path: &str, permalink: &str) -> bool {
+    let library_page_translations = Translations::for_path(site, path);
+    let translations_permalinks = library_page_translations.permalinks();
+
+    let output_path = permalink.trim_start_matches(&site.config.base_url);
+    // Strip leading / so it's not interpreted as an absolute path
+    let output_path = output_path.trim_start_matches('/');
+    // Don't forget to remove / because 
+    let output_path = site.output_path.join(output_path);
+
+    let output = std::fs::read_to_string(&output_path).expect(&format!("Output not found in {}", output_path.display()));
+    
+    for permalink in &translations_permalinks {
+        if !output.contains(permalink) {
+            println!("Page {} has translation {}, but it was not found in output", path, permalink);
+            return false;
+        }
+    }
+
+    return true;
+}
diff --git a/components/site/tests/site_i18n.rs b/components/site/tests/site_i18n.rs
index d4ed0e34..eddbe9a4 100644
--- a/components/site/tests/site_i18n.rs
+++ b/components/site/tests/site_i18n.rs
@@ -2,7 +2,7 @@ mod common;
 
 use std::env;
 
-use common::build_site;
+use common::*;
 use site::Site;
 
 #[test]
@@ -14,7 +14,7 @@ fn can_parse_multilingual_site() {
     site.load().unwrap();
 
     let library = site.library.read().unwrap();
-    assert_eq!(library.pages().len(), 10);
+    assert_eq!(library.pages().len(), 11);
     assert_eq!(library.sections().len(), 6);
 
     // default index sections
@@ -174,3 +174,27 @@ fn can_build_multilingual_site() {
     assert!(file_exists!(public, "search_index.it.js"));
     assert!(!file_exists!(public, "search_index.fr.js"));
 }
+
+#[test]
+fn correct_translations_on_all_pages() {
+    let (site, _tmp_dir, public) = build_site("test_site_i18n");
+
+    assert!(public.exists());
+
+    let translations = find_expected_translations("test_site_i18n", &site.config.default_language);
+
+    for (path, link) in &site.permalinks {
+        // link ends with /, does not add index.html
+        let link = format!("{}index.html", link);
+
+        // Ensure every permalink has produced a HTML page
+        assert!(ensure_output_exists(&public, &site.config.base_url, &link));
+
+        // Ensure translations expected here match with those in the library
+        // TODO: add constructive error message inside the function
+        assert!(ensure_translations_match(&translations, &site, &path));
+
+        // Ensure output file contains all translations URLs
+        assert!(ensure_translations_in_output(&site, &path, &link));
+    }
+}
diff --git a/test_site_i18n/content/_index.fr.md b/test_site_i18n/content/_index.fr.md
new file mode 100644
index 00000000..b7249018
--- /dev/null
+++ b/test_site_i18n/content/_index.fr.md
@@ -0,0 +1,5 @@
++++
+title = "Accueil"
++++
+
+Page d'accueil
diff --git a/test_site_i18n/content/_index.md b/test_site_i18n/content/_index.md
new file mode 100644
index 00000000..814b9a0e
--- /dev/null
+++ b/test_site_i18n/content/_index.md
@@ -0,0 +1,5 @@
++++
+title = "Home"
++++
+
+Homepage
diff --git a/test_site_i18n/content/blog/not-translated-in-default-language.fr.md b/test_site_i18n/content/blog/not-translated-in-default-language.fr.md
new file mode 100644
index 00000000..a918561c
--- /dev/null
+++ b/test_site_i18n/content/blog/not-translated-in-default-language.fr.md
@@ -0,0 +1,5 @@
++++
+title = "Ma page que en français"
++++
+
+Cette page n'est pas traduite dans la langue par défaut (anglais).
diff --git a/test_site_i18n/templates/index.html b/test_site_i18n/templates/index.html
index e1b47f13..1f5e03c9 100644
--- a/test_site_i18n/templates/index.html
+++ b/test_site_i18n/templates/index.html
@@ -2,3 +2,7 @@
     {{page.title}}
 {% endfor %}
 Language: {{lang}}
+
+{% for t in section.translations %}
+Translated in {{t.lang|default(value=config.default_language)}}: {{t.title}} {{t.permalink|safe}}
+{% endfor %}